On Jan. 6, 2018, the Government of Canada published a proposed plan to prohibit (ban) "the import and uses of asbestos and products containing asbestos in Canada, with limited exclusions".
A public comment period is now in effect until March 22 of 2018.
Exclusions, which are subject to limitations as noted in the document, include
1. (use of) mining residues. The following uses of mining residues will however be prohibited:
a. "the sale and use of asbestos mining residues for construction and landscaping activities, unless authorized by the province"; and
b. "the use of asbestos mining residues to manufacture a product that contains asbestos".
2. a time-limited exclusion for the import and use of asbestos in the chlor-alkali industry, until December 31, 2025;
3. an ongoing exclusion for the import, sale and use of asbestos and products containing asbestos for the purpose of display in a museum; and
4. an ongoing exclusion for the import, sale and use of asbestos and products containing asbestos for scientific research, for sample characterization or as an analytical standard in a laboratory.
In addition, an approach to "completely prohibit asbestos was considered", but rejected, with the rationale that "Historically, asbestos has been used in numerous applications, mainly for insulating buildings and homes, as well as for fireproofing. Asbestos has also been used historically in cement, insulation, textiles and filters. As a result of decades of use, many products and installations, including buildings and homes, still contain asbestos. For the most part, health risks are low if the products containing asbestos, such as insulation, are left in place. Requiring all asbestos to be removed from sources such as buildings and homes would be extremely costly and may actually lead to more harm to human health").
Readers should consult the full document and references and footnotes therein for further reference.
NOVEMBER 2015: EPA RELEASES FINAL HUMAN HEALTH RISK ASSESSMENT (HHRA) FOR LIBBY, MONTANA
In a news release dated November 20, 2015, EPA finalizes Human Health Risk Assessment for Libby Asbestos Superfund site
1.The EPA Superfund Program: LIBBY ASBESTOS SITE, LIBBY, MT page is here: Click here to access
2. The Superfund Site: LIBBY ASBESTOS SITE (EPA ID: MT0009083840) "Collection" of Libby Risk Assessments, with titles, dates, and links, is here: Click here to access the pdf.
3. The Superfund Site: LIBBY ASBESTOS SITE (EPA ID: MT0009083840) "Collection" of Libby Risk Assessments, with titles, dates, and links, is here: Click here to access
4. The Human Health Risk Assessment Document itself is an 18 MB download.
TITLE: FINAL "Site-Wide Human Health Risk Assessment / Libby Asbestos Superfund Site, Libby, Montana", attributed to CDM Smith, CDM Federal Programs Corporation, Under a contract with:U.S. Army Corps of Engineers, Omaha District Contract No. W9128F-11-D-0023, Task Order No.: 0007, REVIEWED BY David L. Berry Region 8 (signed November 20, 2015), and by Deborah McKean on the same date, and APPROVED BY Rebecca Thomas (EPA Region 8) and Mary Darling (USACE, Libby Asbestos Superfund Site, Project Manager) on November 20, 2015.
You can download the document if your browser is up to it by CLICKING HERE TO DOWNLOAD THE EPA HHRA FINAL VERSION FOR LIBBY MONTANA
Because EPA pages are currently in the process of restructuring, I have archived a COPY of the final November EPA HHRA for Libby HERE ON MY WEBSITE: Please refer to the original EPA site above if possible.
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A COLLECTION OF DOCUMENTS REGARDING STUDIES OF TREMOLITE ASBESTOS EXPOSURE IN EL DORADO COUNTY, CALIFORNIA
It has been brought to my attention that a link from the EPA web page on naturally occurring asbestos (NOA) in El Dorado county to some animal studies of exposure there is broken. Therefore, here are some related references:
1. This is a peer-reviewed study from Inhaled Particles (British Occupational Hygiene Society) from 2009; the second of the two counties described is El Dorado County and the most up-to-date account of the animal studies is there. Click here to access
2. This is a student project from the McGill School of Environment in 2008. Although it is dated earlier, the information in it includes additional information on the tremolite problem in El Dorado county as well as a survey of residents done in the County and more information on the animal study Click here to access the pdf.
3. EPA's initial investigations in El Dorado county are as described elsewhere. However, from other sources and from our animal studies (above) we can see that there are areas of western El Dorado county which have longer tremolite fibers of probable greater health concern. Coincidentally, USGS scientists sampled the exact area from which the dogs and cats we studied came, and published them as:
Lowers, H.A., and Meeker, G.P., 2007, Denver microbeam laboratory administrative report 30112006: U.S. Geological Survey Administrative Report, 12 p.
At the request of EPA, the authors conducted "...an evaluation for the presence of fibrous and asbestiform
amphiboles in soil and rock samples collected from a specific road cut in El Dorado County" which coincidentally was in the same area as the habitat our animals. Fibers identified and pictured were asbestiform, "...fall(ing) completely within the tremolite and actinolite fields, respectively, as defined by Leake and others (1997)". Click here to access the pdf.
4. Earlier, a presentation was put together by Dr. J. Abraham (SUNY-Syracuse), myself, Mr. Terry Trent and Mr. Brian Burnett for EPA use. This is the study with a broken link on EPA's El Dorado NOA page; Click here to access a copy.
5. A poster presentation of (4), above, was presented to the American Thoracic Society after acceptance by that body at their annual meeting in 2005. Click here to access a copy of the abstract, and here to see the poster itself.
Re Better Planning, Execution and Communication Could Have Reduced the Delays in Completing a Toxicity Assessment of the Libby, Montana, Superfund Site: United States EPA Office of Inspector General Report No. 13-P-0221 issued April 17, 2013
(CLICK ABOVE LINK to download report from the EPA website)
The above extensive report with responses from EPA and responses from OIG to EPA critique further extends the below discussion extending from the FINAL REPORT (January 30, 2013) of the United States EPA (and its Science Advisory Board, by Extension) in re EPA’s draft Integrated Risk Information System (IRIS) assessment, entitled Toxicological Review of Libby Amphibole Asbestos (August 2011). Disagreements between EPA and its OIG are extensive (EPA agrees with only ONE of nine recommendations made) and must be resolved. I will not attempt to characterize the OIG document here, please consult the original.
Re IRIS Assessment for Libby Amphibole Asbestos:
THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY SCIENCE ADVISORY BOARD (SAB) has on January 30, 2013 issued it's FINAL REPORT ON "a peer review of EPA’s draft Integrated Risk Information System (IRIS) assessment, entitled Toxicological Review of Libby Amphibole
Asbestos (August 2011)".
Few changes have been made to the previous drafts. There are some contradictions between the cover letter, "Executive Summary", and full report. It is not specified when or if the SAB evaluation of the EPA study will be incorporated into the formal IRIS risk assessment.
For those who wish to you can TO GO BACK TO THE BACKGROUND of what this whole exercise was supposed to do; I reproduce part of THE BACKGROUND BOX TEXT ON THIS WEB PAGE below:
"This draft health assessment of the toxicity of Libby amphibole asbestos was prepared by staff in both EPA’s Region 8 Office and ORD/NCEA. The assessment is focused on a specific type of asbestos found as a consequence of the mining and processing of vermiculite in Libby, Montana. The assessment will be included on EPA's IRIS data base when finalized. The project supports OSWER and Region 8 site clean-up and related risk management initiatives at the Libby Superfund site. As with all IRIS assessments, the development of this external peer review draft document required internal EPA review and OMB/interagency review. After an independent external peer review, the draft final document will undergo a second round of EPA and OMB/interagency review before being finalized and then included on the IRIS data base.
Libby Amphibole asbestos is a complex mixture of amphibole fibers, both mineralogically and morphologically. The mixture primarily includes tremolite, winchite, and richterite fibers with trace amounts of magnesioriebeckite, edenite, and magnesio-arfvedsonite. These fibers exhibit a range of morphologies (e.g. prismatic, ascicular, asbestiform)(Meeker et al., 2003).
Exposure to Libby Amphibole asbestos results in the same types of adverse health effects as are seen with exposure to other amphibole mineral fibers. Epidemiologic studies of workers exposed to Libby Amphibole asbestos fibers indicate increased mortality from lung cancer, mesothelioma, asbestosis, and other nonmalignant respiratory diseases (McDonald et al., 1986a, 2004; Amandus and Wheeler, 1987; Amandus et al., 1987a; Sullivan, 2007; Larson et al., 2010a, Moolgavkar et al., 2010). Morbidity studies report increased asbestosis, pleural thickening and decreased lung function in exposed individuals (Weill et al., 2010; Larson et al., 1020b; Rohs et al., 2008, Peipens et al., 2003, ATSDR, 2001; Amandus et al., 1987b and McDonald et al., 1986 b.)
History/Chronology
Aug 2007 The Libby Amphibole Asbestos assessment was initiated in 2007. It was nominated for assessment by the IRIS Program because it supports OSWER and Region 8 site clean-up and related risk management initiatives at this Superfund site. An assessment for Libby Amphibole Asbestos is not currently on IRIS.
May 2011 EPA hosted an interagency science consultation on the draft IRIS Toxicological Review of Libby Amphibole Asbestos.
Aug 2011 EPA released the draft IRIS Toxicological Review of Libby Amphibole Asbestos for public review and comment, and announced the public listening session. [Federal Register Notice Aug 25, 2011]
Dec 2011 EPA's Science Advisory Board announced a public peer review meeting on the draft IRIS Toxicological Review of Libby Amphibole Asbestos that was held on Feb 6 -8, 2012 in Alexandria, VA. [Federal Register Notice Dec 23, 2011]
Next Steps
Following external peer review, the assessment will be revised taking into consideration external peer review and public comments. It will then be revised as appropriate and will undergo a final EPA internal review and a science discussion with other federal agencies and White House offices, and will be posted to the IRIS database. This Assessment does not replace the existing IRIS listing for asbestos (EPA, 1988).
Citation
U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002A, 2011."
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The SAB has also in its deliberations made regularly available some additional reviewer and public comments from later in July 2012. Particularly noteworthy are the EPA "Agency Comment" (response) from David Bussard, dated July 24, 2012, on Questions and Clarifications related to SAB July Draft Report, the Comments From (panel member) Dr.Mort Lippmann In Response To Memo from David Bussard , and Public Comments from Dr. Suresh Moolgavkar of Exponent, Inc. both BEFORE an SAB Libby Amphibole Asbestos Review Panel Public Teleconference on July 25, 2012 and afterwards.
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A new COMMENTARY has been published online by the Annals of Occupational Hygiene by Drs. D.W. Berman and B.W. Case, entitled " Overreliance on a single study: There is no real evidence that applying quality criteria to exposure in asbestos epidemiology affects the estimated risk".
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THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY CONVENED ITS SCIENCE ADVISORY BOARD AD HOC ASBESTOS REVIEW PANEL RE "IRIS Toxicological Review of Libby Amphibole Asbestos" IN EARLY FEBRUARY. Some panel members submitted pre-meeting comments, and EPA also published submitted public comments on this page.
EPA HAD ON DECEMBER 23, 2011 ANNOUNCED it's Science Advisory Board Ad Hoc Asbestos Review Panel's MEMBERSHIP and the basis for selection (PDF) for review of the IRIS Assessment for Libby Amphibole Asbestos.
Members of the Libby Amphibole Asbestos Review Panel are also listed HERE.
THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY, ON AUGUST 25, 2011, ANNOUNCED IMPORTANT DEVELOPMENTS WITH RESPECT TO THE "U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002C, 2011."
The relevant page from EPA's Integrated Risk Information System (IRIS) with links to relevant documents may be accessed by clicking HERE.
In so doing, EPA has performed several important actions:
1. The DRAFT DOCUMENT from August 2011 (which is not to be cited or quoted)regarding a TOXICOLOGICAL REVIEW OF LIBBY AMPHIBOLE ASBESTOS, which is "an assessment of the noncancer and cancer health effects associated with the inhalation route of exposure only", is published as a downloadable PDF file.
It is important to note that this document is "...a preliminary draft for review purposes only...distributed solely for the purpose of predissemination peer review under applicable information quality guidelines".
2. Simultaneously, EPA "announces the release of the IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft) for public viewing and comment". This DRAFT is open to Public Comment for 60 days. The deadline for comments is October 24, 2011. In the interim, EPA offers to hold a "public listening session" regarding the draft in Arlington, VA, on October 6, 2011, beginning at 1 p.m. and ending at 5 p.m., Eastern Daylight Time, or when the last presentation has been completed. Those attending may simply "listen" or may make presentations of up to 30 minutes duration. My understanding of the notice is that if NO such presentations are requested THE SESSION WILL BE CANCELLED. Full details as to attendance and/ or submission of presentations (which must occur by September 29, 2011) are provided in a COMPANION FEDERAL REGISTER NOTICE.
3. Simultaneously, EPA releases a draft NCEA Proposed Draft Charge to External Reviewers for the IRIS Toxicological Review of Libby Amphibole Asbestos. It is not clear from the NOTICE whether this DRAFT is also open to Public Comment for 60 days. The CHARGE QUESTIONS will presumably be considered by the Ad Hoc Panel (of External Reviewers) that is being formed for the EPA Science Advisory Board (SAB) on the subject of the IRIS Assessment for Libby Amphibole Asbestos. Announcement of the membership of this committee has not, to my knowledge, been made, but the public comment period regarding NOMINATED PERSONS (CLICK HERE) has ended. (The announcement for nomination was made on May 27, 2011; nominations were accepted until June 17, 2011, and the Public Comment Period on nominees began August 9 and was closed August 30, 2011.
4. Finally, it should be noted that the new (AUGUST 2011) U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002C, 2011 should not be confused with the earlier document issued in May of 2011. In the interim EPA received comments and advice from other US agencies. EPA has published responses to these comments in association with release of the latest Draft.
Interested observers in Libby and elsewhere should watch the EPA SAB website for further news of the Ad Hoc Panel considerations, which will presumably also be followed by further internal EPA review and public comment period(s).
All of the above is based on my own understanding of the EPA process; document links are provided as a courtesy to readers and are best accessed from the relevant US Government websites directly, as changes are always possible.
A NEW SERIES OF ARTICLES ON "MODE OF ACTION" OF "ASBESTOS" AND OTHER TOPICS
was moved online to the new TAYLOR AND FRANCIS WEBSITE JUNE 2011, with open access, in Journal of Toxicology and Environmental Health, Part B: Critical Reviews.
The journal publishes a series of critical reviews of "asbestos", with the goal of informing on the mode of action of asbestos and determining data gaps and research needs in the field. Process for the production of these papers began with a Workshop held in November of 2009 in Chapel Hill, NC of the National Institute for Environmental Health Sciences (NIEHS). The workshop was supported by NIEHS, National Toxicology Program, U.S. Environmental Protection Agency (Office of Research and Development, Office of Solid Waste and Emergency Response), and the Centers for Disease Control and Prevention (Agency for Toxics Substances and Disease Registry, National Institute for Occupational Safety and Health). It should be noted that all findings are those of the authors and do not necessarily represent the views of the NIEHS or the other sponsoring government agencies.
One article by this author and colleagues Jerrold Abraham, Greg Meeker, Fred Pooley, and Kent Pinkerton discusses
ways in which definitions of “Asbestos” apply to environmental and “low-dose” exposure levels and health effects, with an emphasis on malignant mesothelioma.
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On June 13, 2011, a group of Canadian and International organizations and scientists released a letter to Prime Minister Stephen Harper of Canada urging the Canadian Government to support the listing of chrysotile asbestos in the PIC (Prior Informed Consent) List under the Rotterdam Convention, at the Meeting of the Parties to that Convention in June of 2011. Per the letter, the purpose of the Rotterdam Convention is to bring about responsible trade of hazardous substances by requiring that exporting countries obtain “prior informed consent” before shipping substances, which are on the Convention’s list, to another country. The letter is available here.
UPDATE: According to the Toronto Globe and Mail and Reuters this effort has failed, not for the first time. It is only to be hoped that at the 2013 meeting the government will come to its senses and allow the listing. This has been the position of our Research Community in Canada for some time now.
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HEALTH CANADA has made the Chrysotile Asbestos Consensus Statement and Summary
available to "members of the public". It does not yet appear on the HC website. As a great deal of misinformation has been in the popular press about this report you can read it here and judge for yourself.
My own impression: It basically follows (and compares) the findings of three studies; that of Hodgson and Darnton (Ann Occup Hygiene 2000) and the two (published since the Panel report was written) of Berman and Crump, namely
A meta-analysis of asbestos-related cancer risk that addresses fiber size and mineral type and
Update of potency factors for asbestos-related lung cancer and mesothelioma
The Panel report has the usual and inevitable watered-down quality of any "consensus" statement that involves a small (six people) group of people with, in the words of Panel Chair Trevor Ogden, "...members who in the past have expressed strongly opposed views on this subject". It is nevertheless a solid achievement, and should have been published long ago.
Dr. Ogden in his cover letter (see report) also notes re the panel members that "Thanks are due to them for their willingness to work to find a common position as far as possible. Getting them to participate at fairly short notice was itself a significant achievement, for which Dr. Michel Camus and Health Canada staff deserve major credit".
It should also be noted that this is NOT a "Health Canada Report" per se; the title page disclaims:
"This report was written by the Chair and members of the Expert Panel, and the opinions
expressed therein do not necessarily reflect the views of Health Canada".
Again quoting the Chair,
"The Panel supported the approach of two major reviews, which give information on the relationship of the cancers to chrysotile exposure. Generally these show a strong relationship of exposure with lung cancer, but a much less certain relationship with mesothelioma. However, the Consensus Statement and Summary should be consulted for details".
RECENT PUBLICATION ON MESOTHELIOMA RISK IN TWO AMERICAN COUNTIES
We (myself and Dr. Jerrold Abraham) have recently published following peer review and presentation at Inhaled Particles X Heterogeneity of exposure and attribution of mesothelioma: Trends and strategies in two American counties, using lung-retained fiber as an exposure index. This was possible in human mesothelioma cases in Jefferson Parish, Louisiana, where there is an ongoing mesothelioma epidemic - by absolute numbers, the most serious in North America - due to previous manufacturing (epecially at the Johns Manville cement pipe plant there); past shipyard exposures; and especially the practice of the Johns Manville plant of distributing crocidolite-laden scrap to be used in driveways, roads, daycares, schoolyards, etc. all over the neighborhoods of six cities in the county. A map of a small fraction of the sites involved, not all of which were remediated, may be found in the textbook Asbestos and its Diseases edited by Craighead and Gibbs (on page 81).
The other county is of course El Dorado County, California, where risk which has long been suspected is confirmed by the analysis of dog lungs from the area (since publication we have at our lab in Montreal also found that there are no fibers at all in the lungs of control dogs).
TALC, CONTINUED:
In their most recent meeting for a new monograph (Volume 93), IARC assessed among other chemicals "non-asbestiform talc". While the monograph may not be available for some time, a brief summary has been posted online by IARC in pdf format. The principal finding was that "Inhaled talc not containing asbestos or asbestiform fibres is not classifiable as to its carcinogenicity to humans (Group 3). A separate assessment however was made for "Perineal use of talc-based body powder", considered on the strength of the evidence to be "possibly carcinogenic to humans (Group 2B)". Finally, none of this applies of course to talc which IS ASBESTIFORM (which does not mean that the talc CONTAINS asbestos); IARC notes that for example "Mineral talc is usually platy but may also occur as asbestiform fibres...Asbestiform talc must not be confused with talc that contains asbestos... Together with platy talc, asbestiform talc is found in the Gouverneur District of New York State, USA, and occasionally elsewhere; it may be associated with other minerals as observed by transmission electron microscopy".
For further discussion of New York State Gouverneur District abestiform talc and its consequences, please click and read the paper from Dr. Abraham (SUNY Syracuse) and myself entitled Mesothelioma among Workers in Asbestiform Fiber-bearing Talc Mines in New York State published in the Annals of Occupational Hygiene in 2002.
A2006 paper indexed on PUBMED on the Mineralogical and exposure determinants of pulmonary fibrosis among Quebec chrysotile miners and millers has been published in the March 2006 issue of Int Arch Occup Environ Health.
ABSTRACT:
Nayebzadeh A, Case BW, Masse J, Dufresne A. Mineralogical and exposure determinants of pulmonary fibrosis among Quebec chrysotile miners and millers. Int Arch Occup Environ Health 2006 Mar;79(3):227-36.
Objectives: Lung fibre content was determined for 86 former chrysotile miners and millers in two Quebec mining regions: Thetford mines (TM) and the Asbestos region (AR).
Methods: Fibres were assessed using transmission electron microscopy (TEM) and energy dispersive X-ray spectrometry (EDS). Asbestos body (AB) concentrations were assessed by microscopy of tissue digests. Corresponding histological lung tissue sections were quantitatively graded for the severity of interstitial fibrosis on a 12-point scale. Fibrosis score and its associations with (1) fibre concentrations and fibre dimensions within three fibre length intervals (less than 5 um, 5-10 um, and over 10 um), and (2) several exposure variables were evaluated using correlation coefficients and regression techniques.
Results: Concentration of short (<5 um) tremolite fibres was the best predictor of fibrosis grade in both mining groups (r=0.44, P<0.01 and r=0.39, P<0.01 for TM and AR, respectively). Chrysotile fibre concentration showed a lower correlation with the fibrosis grade for subjects from TM only. Long (>10 um) amosite fibre concentration showed a linear relationship with the fibrosis score in miners and millers from AR. Exposure variables, including smoking, had no predictive value for fibrosis grade. Within fibre length categories, fibre dimension was not related to the fibrosis score.
Conclusion: Lung fibre concentration as measured by TEM/EDS, especially that of short (<5 um) tremolite fibres, is a better predictor of fibrosis grade in these two groups of chrysotile miners than either the concentration of ABs or the duration of exposure. Due to the limitation of our counting method, almost all fibres longer than 10 um observed in this study were shorter than 14 um. Thus, if length plays a role in fibrogenesis, it may be related to fibres of greater length than those covered in this study.
PMID: 16283364 [PubMed - in process]
The SITUATION IN EL DORADO COUNTY, CALFORNIA regarding environmental tremolite exposure is receiving increasing scientific and public health attention. The November issue of ENVIRONMENTAL HEALTH PERSPECTIVES contains an article noting the considerable risk there. See
SHOWDOWN IN EL DORADO
; also you can watch video of recent news coverage by CBS; click here or go to the CBS video search page; search for ASBESTOS and click the item "playing with asbestos".
EPA has reported the results of an active air sampling done in the area in October of 2004. Results were criticized by a mining industry lobby group based on a report from their consultant R.J. Lee. These have been addressed with devastating accuracy and comprehensive detail by the April 20, 2006 Response to the November 2005 National Stone, Sand & Gravel Association Report Prepared by the R.J. Lee Group, Inc “Evaluation of EPA’s Analytical Data from the El Dorado Hills Asbestos Evaluation Project”
Discussion of the issues is beyond the scope here, but essentially the arguments boil down to the "cleavage fragments versus asbestos fibres" issue which has been extant since at least 1990, when the ATS Official Statement on Tremolite was issued (relevant portions highlighted; and 1992, when OSHA deregulated "nonasbestiform" tremolite, anthophyllite, and actinolite. The debate on the issues continues, with an EPA expert panel on which this writer served again disputing the OSHA findings in May 2003.
The relevant portion of the panel report for EPA is archived HERE.
Most recently EPA had been criticized by their own IG in regards to Libby, Montana amphibole exposure for inadequate characterization. An interesting article that describes this and related issues was recently published in ENVIRONMENTAL SCIENCE & TECHNOLOGY
by Rebecca Renner.
Getting back to El Dorado County itself, all parties agree that the asbestiform variant of tremolite
occurs in western El Dorado county (and indeed on the western slope of the Sierras). Our own presentation of lung-retained tremolite fibres in area pets (see below) was presented at the American Thoracic Society in San Diego. It was published on page A818 of the Abstract Volume (Supplement to the April number of volume 171) of the American Journal of Respiratory and Critical Care Medicine. You can click here to see a copy. A link to the study has been posted on the El Dorado Hills, Naturally Occurring Asbestos EPA WebSite for Region 9.
Many recent newspaper articles on the subject have also appeared in the Sacramento Bee and elsewhere (you will have to register with the site and search for stories about "asbestos").
The important point is made vis-a-vis Libby Montana - the risk in terms at least of numbers of cases of future mesothelioma seems much greater in Western El Dorado County, based on the larger population there.
The risk in Libby and in El Dorado can be estimated by reference to McDonald et al. (Occupational and Environmental Medicine 2004;61:363-366) as follows:
"over a lifetime of, say, 50 years, an ambient exposure level of 0.1 f/ml would imply under this model an excess risk of 3.2% in all-cause mortality (RR=1.032)— a not insignificant impact. Exposures of this magnitude may indeed be relevant to the residents of Libby, Montana and perhaps even in some construction areas in northern California".
The SUMMARY of the data prepared for presentation on DOG LUNG TREMOLITE FIBER CONTENT from animals living in El Dorado County, California, made available recently at the EPA-sponsored conference on August 18, 2004, by our McGill lab and Dr. Jerrold Abraham's SUNY Syracuse lab is available HERE as a PDF format file.
A new Official Statement of the American Thoracic Society
titled Diagnosis and Initial Management of Nonmalignant Diseases Related to Asbestos
has been released and published in the American Journal of Respiratory and Critical Care Medicine. This Statement, which replaces the 1986 ATS statement and has been worked on by the authors since 2001, deals with diagnosis and management of non-malignant diseases only. It has been much awaited and has already engendered much discussion among interested scientists. Unlike previous ATS statements on this topic, it is rather vague in actual disease definition, although retaing the 1982 1982 College of American Pathologists PATHOLOGIC definition of "asbestosis". You can access the report at the http://www.thoracic.org website of the ATS CLICKING HERE.
The 1990 statement on HEALTH EFFECTS OF TREMOLITE is archived here; currently an ATS EOH committee is working on a NEW tremolite report.
RECENT ASBESTOS REPORTS COMMISSIONED BY GOVERNMENT AGENCIES
The Quebec National Institute of Public Health (INSPQ) has released two separate reports, both in French initially and then in English at a later date.
INSPQ on their web site offers the following summary rationale for the production and issuance of these reports:
In 1997, in light of international developments with respect to asbestos, particularly after its banning in France, Quebec’s ministère de la Santé et des Services sociaux (department of health and social services) set up a Comité aviseur sur l’amiante (asbestos advisory committee). The aim of this committee was to make recommendations about appropriate measures to inform the public and to protect public health in relation to the asbestos situation in Quebec. The advisory committee then created two sub-committees: the first to document asbestos exposure and the second to examine the epidemiology of asbestos-related diseases in Quebec. The sub-committee on exposure was mandated to assess the pertinence and the feasibility of assessing asbestos exposure in the general population, particularly in public buildings such as schools. The sub-committee on epidemiology was mandated to review epidemiological studies available in Quebec on mesothelioma, pulmonary cancers, and asbestosis; evaluate the trends of these diseases; compare data from Quebec to those of other regions; and summarize current scientific knowledge on the effects of asbestos on health. Each sub-committee produced a report, the summaries and recommendations of which are presented here.
The ENGLISH PUBLICATIONS PAGE of the INSPQ has an ENGLISH TRANSLATION OF A SUMMARY OF THESE TWO REPORTS .
FULL English translations of both the 
Epidemiology Report
and the Report of the Sub-committee on Exposure titled 
ASBESTOS FIBRES IN INDOOR AND OUTDOOR AIR - THE SITUATION IN QUEBEC have now been published.
PLEASE NOTE: This material is copyright
and may not be reproduced for commercial purposes, although non-commercial use is permitted provided the full source material(s) are cited. See the publications for details.
Please note as well that ONLY translations obtained from INSPQ are official
, and any other translation is unacceptable and unlawful; use of the official INSPQ documents and official INSPQ translations should be governed by the copyright notices within the publications, each of which bears an ISBN publication number.
As part of the IRIS risk assessment process, the United States Environmental protection agency is holding a series of EXPERT PANEL MEETINGS. EPA stated in their NOTICE in the Federal Register (FR Vol. 68, No. 24 / Wednesday, February 5, 2003 / Notices/ page 5873) that
"EPA’s current assessment of asbestos toxicity is based primarily on an asbestos assessment completed in 1986, and EPA’s assessment has not changed substantially since that time. The 1986 assessment considers all mineral forms of asbestos and all asbestos fiber sizes (i.e., all fibers longer than 5 micrometers) to be of equal carcinogenic potency. However, since 1986, there have been substantial improvements in asbestos measurement techniques and in the understanding of how asbestos exposure contributes to disease. To incorporate the knowledge gained over the last 17 years into the agency’s toxicity assessment for asbestos, EPA oversaw the development of a revised methodology for conducting risk assessments of asbestos. The proposed risk assessment methodology distinguishes between fiber sizes and fiber types in estimating potential health risks related to asbestos exposure."
A peer review expert panel considered the above-mentioned "revised methodology" at the February 2003 workshop and the proceedings and appendices were published May 30, 2003 as EPA Contract Number 68-C-98-148, Work Assignment 2003-05, prepared by Eastern Research Group, Inc.
Because the EPA website is under constant revision and files may become unaccessible, the MAIN BODY OF THE REPORT IS ALSO ARCHIVED HERE
. To access and view the ARCHIVED APPENDICES TO THE REPORT, CLICK HERE.
Following this peer review the authors of the proposed methodology for EPA prepared a "Final Draft" guidance document for EPA's Office of Solid Waste and Emergency Response (U.S. Environmental Protection Agency Washington, DC 20460; EPA # 9345.4-06; October 2003). This DRAFT GUIDANCE DOCUMENT titled FINAL DRAFT: TECHNICAL SUPPORT DOCUMENT FOR A PROTOCOL TO ASSESS ASBESTOS-RELATED RISK" is archived in two parts here.
The first five chapters can be viewed by clicking HERE. The final chapters (six to nine)are archived HERE.
APPENDICES to this report (five in number) are archived HERE.
Because EPA pages are currently in the process of restructuring, I have archived a COPY of the final November EPA HHRA for Libby HERE ON MY WEBSITE: Please refer to the original EPA site above if possible.
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A COLLECTION OF DOCUMENTS REGARDING STUDIES OF TREMOLITE ASBESTOS EXPOSURE IN EL DORADO COUNTY, CALIFORNIA
It has been brought to my attention that a link from the EPA web page on naturally occurring asbestos (NOA) in El Dorado county to some animal studies of exposure there is broken. Therefore, here are some related references:
1. This is a peer-reviewed study from Inhaled Particles (British Occupational Hygiene Society) from 2009; the second of the two counties described is El Dorado County and the most up-to-date account of the animal studies is there. Click here to access
2. This is a student project from the McGill School of Environment in 2008. Although it is dated earlier, the information in it includes additional information on the tremolite problem in El Dorado county as well as a survey of residents done in the County and more information on the animal study Click here to access the pdf.
3. EPA's initial investigations in El Dorado county are as described elsewhere. However, from other sources and from our animal studies (above) we can see that there are areas of western El Dorado county which have longer tremolite fibers of probable greater health concern. Coincidentally, USGS scientists sampled the exact area from which the dogs and cats we studied came, and published them as:
Lowers, H.A., and Meeker, G.P., 2007, Denver microbeam laboratory administrative report 30112006: U.S. Geological Survey Administrative Report, 12 p.
At the request of EPA, the authors conducted "...an evaluation for the presence of fibrous and asbestiform
amphiboles in soil and rock samples collected from a specific road cut in El Dorado County" which coincidentally was in the same area as the habitat our animals. Fibers identified and pictured were asbestiform, "...fall(ing) completely within the tremolite and actinolite fields, respectively, as defined by Leake and others (1997)". Click here to access the pdf.
4. Earlier, a presentation was put together by Dr. J. Abraham (SUNY-Syracuse), myself, Mr. Terry Trent and Mr. Brian Burnett for EPA use. This is the study with a broken link on EPA's El Dorado NOA page; Click here to access a copy.
5. A poster presentation of (4), above, was presented to the American Thoracic Society after acceptance by that body at their annual meeting in 2005. Click here to access a copy of the abstract, and here to see the poster itself.
Re Better Planning, Execution and Communication Could Have Reduced the Delays in Completing a Toxicity Assessment of the Libby, Montana, Superfund Site: United States EPA Office of Inspector General Report No. 13-P-0221 issued April 17, 2013
(CLICK ABOVE LINK to download report from the EPA website)
The above extensive report with responses from EPA and responses from OIG to EPA critique further extends the below discussion extending from the FINAL REPORT (January 30, 2013) of the United States EPA (and its Science Advisory Board, by Extension) in re EPA’s draft Integrated Risk Information System (IRIS) assessment, entitled Toxicological Review of Libby Amphibole Asbestos (August 2011). Disagreements between EPA and its OIG are extensive (EPA agrees with only ONE of nine recommendations made) and must be resolved. I will not attempt to characterize the OIG document here, please consult the original.
Re IRIS Assessment for Libby Amphibole Asbestos:
THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY SCIENCE ADVISORY BOARD (SAB) has on January 30, 2013 issued it's FINAL REPORT ON "a peer review of EPA’s draft Integrated Risk Information System (IRIS) assessment, entitled Toxicological Review of Libby Amphibole
Asbestos (August 2011)".
Few changes have been made to the previous drafts. There are some contradictions between the cover letter, "Executive Summary", and full report. It is not specified when or if the SAB evaluation of the EPA study will be incorporated into the formal IRIS risk assessment.
For those who wish to you can TO GO BACK TO THE BACKGROUND of what this whole exercise was supposed to do; I reproduce part of THE BACKGROUND BOX TEXT ON THIS WEB PAGE below:
"This draft health assessment of the toxicity of Libby amphibole asbestos was prepared by staff in both EPA’s Region 8 Office and ORD/NCEA. The assessment is focused on a specific type of asbestos found as a consequence of the mining and processing of vermiculite in Libby, Montana. The assessment will be included on EPA's IRIS data base when finalized. The project supports OSWER and Region 8 site clean-up and related risk management initiatives at the Libby Superfund site. As with all IRIS assessments, the development of this external peer review draft document required internal EPA review and OMB/interagency review. After an independent external peer review, the draft final document will undergo a second round of EPA and OMB/interagency review before being finalized and then included on the IRIS data base.
Libby Amphibole asbestos is a complex mixture of amphibole fibers, both mineralogically and morphologically. The mixture primarily includes tremolite, winchite, and richterite fibers with trace amounts of magnesioriebeckite, edenite, and magnesio-arfvedsonite. These fibers exhibit a range of morphologies (e.g. prismatic, ascicular, asbestiform)(Meeker et al., 2003).
Exposure to Libby Amphibole asbestos results in the same types of adverse health effects as are seen with exposure to other amphibole mineral fibers. Epidemiologic studies of workers exposed to Libby Amphibole asbestos fibers indicate increased mortality from lung cancer, mesothelioma, asbestosis, and other nonmalignant respiratory diseases (McDonald et al., 1986a, 2004; Amandus and Wheeler, 1987; Amandus et al., 1987a; Sullivan, 2007; Larson et al., 2010a, Moolgavkar et al., 2010). Morbidity studies report increased asbestosis, pleural thickening and decreased lung function in exposed individuals (Weill et al., 2010; Larson et al., 1020b; Rohs et al., 2008, Peipens et al., 2003, ATSDR, 2001; Amandus et al., 1987b and McDonald et al., 1986 b.)
History/Chronology
Aug 2007 The Libby Amphibole Asbestos assessment was initiated in 2007. It was nominated for assessment by the IRIS Program because it supports OSWER and Region 8 site clean-up and related risk management initiatives at this Superfund site. An assessment for Libby Amphibole Asbestos is not currently on IRIS.
May 2011 EPA hosted an interagency science consultation on the draft IRIS Toxicological Review of Libby Amphibole Asbestos.
Aug 2011 EPA released the draft IRIS Toxicological Review of Libby Amphibole Asbestos for public review and comment, and announced the public listening session. [Federal Register Notice Aug 25, 2011]
Dec 2011 EPA's Science Advisory Board announced a public peer review meeting on the draft IRIS Toxicological Review of Libby Amphibole Asbestos that was held on Feb 6 -8, 2012 in Alexandria, VA. [Federal Register Notice Dec 23, 2011]
Next Steps
Following external peer review, the assessment will be revised taking into consideration external peer review and public comments. It will then be revised as appropriate and will undergo a final EPA internal review and a science discussion with other federal agencies and White House offices, and will be posted to the IRIS database. This Assessment does not replace the existing IRIS listing for asbestos (EPA, 1988).
Citation
U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002A, 2011."
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The SAB has also in its deliberations made regularly available some additional reviewer and public comments from later in July 2012. Particularly noteworthy are the EPA "Agency Comment" (response) from David Bussard, dated July 24, 2012, on Questions and Clarifications related to SAB July Draft Report, the Comments From (panel member) Dr.Mort Lippmann In Response To Memo from David Bussard , and Public Comments from Dr. Suresh Moolgavkar of Exponent, Inc. both BEFORE an SAB Libby Amphibole Asbestos Review Panel Public Teleconference on July 25, 2012 and afterwards.
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A new COMMENTARY has been published online by the Annals of Occupational Hygiene by Drs. D.W. Berman and B.W. Case, entitled " Overreliance on a single study: There is no real evidence that applying quality criteria to exposure in asbestos epidemiology affects the estimated risk".
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THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY CONVENED ITS SCIENCE ADVISORY BOARD AD HOC ASBESTOS REVIEW PANEL RE "IRIS Toxicological Review of Libby Amphibole Asbestos" IN EARLY FEBRUARY. Some panel members submitted pre-meeting comments, and EPA also published submitted public comments on this page.
EPA HAD ON DECEMBER 23, 2011 ANNOUNCED it's Science Advisory Board Ad Hoc Asbestos Review Panel's MEMBERSHIP and the basis for selection (PDF) for review of the IRIS Assessment for Libby Amphibole Asbestos.
Members of the Libby Amphibole Asbestos Review Panel are also listed HERE.
THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY, ON AUGUST 25, 2011, ANNOUNCED IMPORTANT DEVELOPMENTS WITH RESPECT TO THE "U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002C, 2011."
The relevant page from EPA's Integrated Risk Information System (IRIS) with links to relevant documents may be accessed by clicking HERE.
In so doing, EPA has performed several important actions:
1. The DRAFT DOCUMENT from August 2011 (which is not to be cited or quoted)regarding a TOXICOLOGICAL REVIEW OF LIBBY AMPHIBOLE ASBESTOS, which is "an assessment of the noncancer and cancer health effects associated with the inhalation route of exposure only", is published as a downloadable PDF file.
It is important to note that this document is "...a preliminary draft for review purposes only...distributed solely for the purpose of predissemination peer review under applicable information quality guidelines".
2. Simultaneously, EPA "announces the release of the IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft) for public viewing and comment". This DRAFT is open to Public Comment for 60 days. The deadline for comments is October 24, 2011. In the interim, EPA offers to hold a "public listening session" regarding the draft in Arlington, VA, on October 6, 2011, beginning at 1 p.m. and ending at 5 p.m., Eastern Daylight Time, or when the last presentation has been completed. Those attending may simply "listen" or may make presentations of up to 30 minutes duration. My understanding of the notice is that if NO such presentations are requested THE SESSION WILL BE CANCELLED. Full details as to attendance and/ or submission of presentations (which must occur by September 29, 2011) are provided in a COMPANION FEDERAL REGISTER NOTICE.
3. Simultaneously, EPA releases a draft NCEA Proposed Draft Charge to External Reviewers for the IRIS Toxicological Review of Libby Amphibole Asbestos. It is not clear from the NOTICE whether this DRAFT is also open to Public Comment for 60 days. The CHARGE QUESTIONS will presumably be considered by the Ad Hoc Panel (of External Reviewers) that is being formed for the EPA Science Advisory Board (SAB) on the subject of the IRIS Assessment for Libby Amphibole Asbestos. Announcement of the membership of this committee has not, to my knowledge, been made, but the public comment period regarding NOMINATED PERSONS (CLICK HERE) has ended. (The announcement for nomination was made on May 27, 2011; nominations were accepted until June 17, 2011, and the Public Comment Period on nominees began August 9 and was closed August 30, 2011.
4. Finally, it should be noted that the new (AUGUST 2011) U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002C, 2011 should not be confused with the earlier document issued in May of 2011. In the interim EPA received comments and advice from other US agencies. EPA has published responses to these comments in association with release of the latest Draft.
Interested observers in Libby and elsewhere should watch the EPA SAB website for further news of the Ad Hoc Panel considerations, which will presumably also be followed by further internal EPA review and public comment period(s).
All of the above is based on my own understanding of the EPA process; document links are provided as a courtesy to readers and are best accessed from the relevant US Government websites directly, as changes are always possible.
A NEW SERIES OF ARTICLES ON "MODE OF ACTION" OF "ASBESTOS" AND OTHER TOPICS
was moved online to the new TAYLOR AND FRANCIS WEBSITE JUNE 2011, with open access, in Journal of Toxicology and Environmental Health, Part B: Critical Reviews.
The journal publishes a series of critical reviews of "asbestos", with the goal of informing on the mode of action of asbestos and determining data gaps and research needs in the field. Process for the production of these papers began with a Workshop held in November of 2009 in Chapel Hill, NC of the National Institute for Environmental Health Sciences (NIEHS). The workshop was supported by NIEHS, National Toxicology Program, U.S. Environmental Protection Agency (Office of Research and Development, Office of Solid Waste and Emergency Response), and the Centers for Disease Control and Prevention (Agency for Toxics Substances and Disease Registry, National Institute for Occupational Safety and Health). It should be noted that all findings are those of the authors and do not necessarily represent the views of the NIEHS or the other sponsoring government agencies.
One article by this author and colleagues Jerrold Abraham, Greg Meeker, Fred Pooley, and Kent Pinkerton discusses
ways in which definitions of “Asbestos” apply to environmental and “low-dose” exposure levels and health effects, with an emphasis on malignant mesothelioma.
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On June 13, 2011, a group of Canadian and International organizations and scientists released a letter to Prime Minister Stephen Harper of Canada urging the Canadian Government to support the listing of chrysotile asbestos in the PIC (Prior Informed Consent) List under the Rotterdam Convention, at the Meeting of the Parties to that Convention in June of 2011. Per the letter, the purpose of the Rotterdam Convention is to bring about responsible trade of hazardous substances by requiring that exporting countries obtain “prior informed consent” before shipping substances, which are on the Convention’s list, to another country. The letter is available here.
UPDATE: According to the Toronto Globe and Mail and Reuters this effort has failed, not for the first time. It is only to be hoped that at the 2013 meeting the government will come to its senses and allow the listing. This has been the position of our Research Community in Canada for some time now.
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HEALTH CANADA has made the Chrysotile Asbestos Consensus Statement and Summary
available to "members of the public". It does not yet appear on the HC website. As a great deal of misinformation has been in the popular press about this report you can read it here and judge for yourself.
My own impression: It basically follows (and compares) the findings of three studies; that of Hodgson and Darnton (Ann Occup Hygiene 2000) and the two (published since the Panel report was written) of Berman and Crump, namely
A meta-analysis of asbestos-related cancer risk that addresses fiber size and mineral type and
Update of potency factors for asbestos-related lung cancer and mesothelioma
The Panel report has the usual and inevitable watered-down quality of any "consensus" statement that involves a small (six people) group of people with, in the words of Panel Chair Trevor Ogden, "...members who in the past have expressed strongly opposed views on this subject". It is nevertheless a solid achievement, and should have been published long ago.
Dr. Ogden in his cover letter (see report) also notes re the panel members that "Thanks are due to them for their willingness to work to find a common position as far as possible. Getting them to participate at fairly short notice was itself a significant achievement, for which Dr. Michel Camus and Health Canada staff deserve major credit".
It should also be noted that this is NOT a "Health Canada Report" per se; the title page disclaims:
"This report was written by the Chair and members of the Expert Panel, and the opinions
expressed therein do not necessarily reflect the views of Health Canada".
Again quoting the Chair,
"The Panel supported the approach of two major reviews, which give information on the relationship of the cancers to chrysotile exposure. Generally these show a strong relationship of exposure with lung cancer, but a much less certain relationship with mesothelioma. However, the Consensus Statement and Summary should be consulted for details".
RECENT PUBLICATION ON MESOTHELIOMA RISK IN TWO AMERICAN COUNTIES
We (myself and Dr. Jerrold Abraham) have recently published following peer review and presentation at Inhaled Particles X Heterogeneity of exposure and attribution of mesothelioma: Trends and strategies in two American counties, using lung-retained fiber as an exposure index. This was possible in human mesothelioma cases in Jefferson Parish, Louisiana, where there is an ongoing mesothelioma epidemic - by absolute numbers, the most serious in North America - due to previous manufacturing (epecially at the Johns Manville cement pipe plant there); past shipyard exposures; and especially the practice of the Johns Manville plant of distributing crocidolite-laden scrap to be used in driveways, roads, daycares, schoolyards, etc. all over the neighborhoods of six cities in the county. A map of a small fraction of the sites involved, not all of which were remediated, may be found in the textbook Asbestos and its Diseases edited by Craighead and Gibbs (on page 81).
The other county is of course El Dorado County, California, where risk which has long been suspected is confirmed by the analysis of dog lungs from the area (since publication we have at our lab in Montreal also found that there are no fibers at all in the lungs of control dogs).
TALC, CONTINUED:
In their most recent meeting for a new monograph (Volume 93), IARC assessed among other chemicals "non-asbestiform talc". While the monograph may not be available for some time, a brief summary has been posted online by IARC in pdf format. The principal finding was that "Inhaled talc not containing asbestos or asbestiform fibres is not classifiable as to its carcinogenicity to humans (Group 3). A separate assessment however was made for "Perineal use of talc-based body powder", considered on the strength of the evidence to be "possibly carcinogenic to humans (Group 2B)". Finally, none of this applies of course to talc which IS ASBESTIFORM (which does not mean that the talc CONTAINS asbestos); IARC notes that for example "Mineral talc is usually platy but may also occur as asbestiform fibres...Asbestiform talc must not be confused with talc that contains asbestos... Together with platy talc, asbestiform talc is found in the Gouverneur District of New York State, USA, and occasionally elsewhere; it may be associated with other minerals as observed by transmission electron microscopy".
For further discussion of New York State Gouverneur District abestiform talc and its consequences, please click and read the paper from Dr. Abraham (SUNY Syracuse) and myself entitled Mesothelioma among Workers in Asbestiform Fiber-bearing Talc Mines in New York State published in the Annals of Occupational Hygiene in 2002.
A2006 paper indexed on PUBMED on the Mineralogical and exposure determinants of pulmonary fibrosis among Quebec chrysotile miners and millers has been published in the March 2006 issue of Int Arch Occup Environ Health.
ABSTRACT:
Nayebzadeh A, Case BW, Masse J, Dufresne A. Mineralogical and exposure determinants of pulmonary fibrosis among Quebec chrysotile miners and millers. Int Arch Occup Environ Health 2006 Mar;79(3):227-36.
Objectives: Lung fibre content was determined for 86 former chrysotile miners and millers in two Quebec mining regions: Thetford mines (TM) and the Asbestos region (AR).
Methods: Fibres were assessed using transmission electron microscopy (TEM) and energy dispersive X-ray spectrometry (EDS). Asbestos body (AB) concentrations were assessed by microscopy of tissue digests. Corresponding histological lung tissue sections were quantitatively graded for the severity of interstitial fibrosis on a 12-point scale. Fibrosis score and its associations with (1) fibre concentrations and fibre dimensions within three fibre length intervals (less than 5 um, 5-10 um, and over 10 um), and (2) several exposure variables were evaluated using correlation coefficients and regression techniques.
Results: Concentration of short (<5 um) tremolite fibres was the best predictor of fibrosis grade in both mining groups (r=0.44, P<0.01 and r=0.39, P<0.01 for TM and AR, respectively). Chrysotile fibre concentration showed a lower correlation with the fibrosis grade for subjects from TM only. Long (>10 um) amosite fibre concentration showed a linear relationship with the fibrosis score in miners and millers from AR. Exposure variables, including smoking, had no predictive value for fibrosis grade. Within fibre length categories, fibre dimension was not related to the fibrosis score.
Conclusion: Lung fibre concentration as measured by TEM/EDS, especially that of short (<5 um) tremolite fibres, is a better predictor of fibrosis grade in these two groups of chrysotile miners than either the concentration of ABs or the duration of exposure. Due to the limitation of our counting method, almost all fibres longer than 10 um observed in this study were shorter than 14 um. Thus, if length plays a role in fibrogenesis, it may be related to fibres of greater length than those covered in this study.
PMID: 16283364 [PubMed - in process]
The SITUATION IN EL DORADO COUNTY, CALFORNIA regarding environmental tremolite exposure is receiving increasing scientific and public health attention. The November issue of ENVIRONMENTAL HEALTH PERSPECTIVES contains an article noting the considerable risk there. See
SHOWDOWN IN EL DORADO
; also you can watch video of recent news coverage by CBS; click here or go to the CBS video search page; search for ASBESTOS and click the item "playing with asbestos".
EPA has reported the results of an active air sampling done in the area in October of 2004. Results were criticized by a mining industry lobby group based on a report from their consultant R.J. Lee. These have been addressed with devastating accuracy and comprehensive detail by the April 20, 2006 Response to the November 2005 National Stone, Sand & Gravel Association Report Prepared by the R.J. Lee Group, Inc “Evaluation of EPA’s Analytical Data from the El Dorado Hills Asbestos Evaluation Project”
Discussion of the issues is beyond the scope here, but essentially the arguments boil down to the "cleavage fragments versus asbestos fibres" issue which has been extant since at least 1990, when the ATS Official Statement on Tremolite was issued (relevant portions highlighted; and 1992, when OSHA deregulated "nonasbestiform" tremolite, anthophyllite, and actinolite. The debate on the issues continues, with an EPA expert panel on which this writer served again disputing the OSHA findings in May 2003.
The relevant portion of the panel report for EPA is archived HERE.
Most recently EPA had been criticized by their own IG in regards to Libby, Montana amphibole exposure for inadequate characterization. An interesting article that describes this and related issues was recently published in ENVIRONMENTAL SCIENCE & TECHNOLOGY
by Rebecca Renner.
Getting back to El Dorado County itself, all parties agree that the asbestiform variant of tremolite
occurs in western El Dorado county (and indeed on the western slope of the Sierras). Our own presentation of lung-retained tremolite fibres in area pets (see below) was presented at the American Thoracic Society in San Diego. It was published on page A818 of the Abstract Volume (Supplement to the April number of volume 171) of the American Journal of Respiratory and Critical Care Medicine. You can click here to see a copy. A link to the study has been posted on the El Dorado Hills, Naturally Occurring Asbestos EPA WebSite for Region 9.
Many recent newspaper articles on the subject have also appeared in the Sacramento Bee and elsewhere (you will have to register with the site and search for stories about "asbestos").
The important point is made vis-a-vis Libby Montana - the risk in terms at least of numbers of cases of future mesothelioma seems much greater in Western El Dorado County, based on the larger population there.
The risk in Libby and in El Dorado can be estimated by reference to McDonald et al. (Occupational and Environmental Medicine 2004;61:363-366) as follows:
"over a lifetime of, say, 50 years, an ambient exposure level of 0.1 f/ml would imply under this model an excess risk of 3.2% in all-cause mortality (RR=1.032)— a not insignificant impact. Exposures of this magnitude may indeed be relevant to the residents of Libby, Montana and perhaps even in some construction areas in northern California".
The SUMMARY of the data prepared for presentation on DOG LUNG TREMOLITE FIBER CONTENT from animals living in El Dorado County, California, made available recently at the EPA-sponsored conference on August 18, 2004, by our McGill lab and Dr. Jerrold Abraham's SUNY Syracuse lab is available HERE as a PDF format file.
A new Official Statement of the American Thoracic Society
titled Diagnosis and Initial Management of Nonmalignant Diseases Related to Asbestos
has been released and published in the American Journal of Respiratory and Critical Care Medicine. This Statement, which replaces the 1986 ATS statement and has been worked on by the authors since 2001, deals with diagnosis and management of non-malignant diseases only. It has been much awaited and has already engendered much discussion among interested scientists. Unlike previous ATS statements on this topic, it is rather vague in actual disease definition, although retaing the 1982 1982 College of American Pathologists PATHOLOGIC definition of "asbestosis". You can access the report at the http://www.thoracic.org website of the ATS CLICKING HERE.
The 1990 statement on HEALTH EFFECTS OF TREMOLITE is archived here; currently an ATS EOH committee is working on a NEW tremolite report.
RECENT ASBESTOS REPORTS COMMISSIONED BY GOVERNMENT AGENCIES
The Quebec National Institute of Public Health (INSPQ) has released two separate reports, both in French initially and then in English at a later date.
INSPQ on their web site offers the following summary rationale for the production and issuance of these reports:
In 1997, in light of international developments with respect to asbestos, particularly after its banning in France, Quebec’s ministère de la Santé et des Services sociaux (department of health and social services) set up a Comité aviseur sur l’amiante (asbestos advisory committee). The aim of this committee was to make recommendations about appropriate measures to inform the public and to protect public health in relation to the asbestos situation in Quebec. The advisory committee then created two sub-committees: the first to document asbestos exposure and the second to examine the epidemiology of asbestos-related diseases in Quebec. The sub-committee on exposure was mandated to assess the pertinence and the feasibility of assessing asbestos exposure in the general population, particularly in public buildings such as schools. The sub-committee on epidemiology was mandated to review epidemiological studies available in Quebec on mesothelioma, pulmonary cancers, and asbestosis; evaluate the trends of these diseases; compare data from Quebec to those of other regions; and summarize current scientific knowledge on the effects of asbestos on health. Each sub-committee produced a report, the summaries and recommendations of which are presented here.
The ENGLISH PUBLICATIONS PAGE of the INSPQ has an ENGLISH TRANSLATION OF A SUMMARY OF THESE TWO REPORTS .
FULL English translations of both the Epidemiology Report
and the Report of the Sub-committee on Exposure titled ASBESTOS FIBRES IN INDOOR AND OUTDOOR AIR - THE SITUATION IN QUEBEC have now been published.
PLEASE NOTE: This material is copyright
and may not be reproduced for commercial purposes, although non-commercial use is permitted provided the full source material(s) are cited. See the publications for details.
Please note as well that ONLY translations obtained from INSPQ are official
, and any other translation is unacceptable and unlawful; use of the official INSPQ documents and official INSPQ translations should be governed by the copyright notices within the publications, each of which bears an ISBN publication number.
As part of the IRIS risk assessment process, the United States Environmental protection agency is holding a series of EXPERT PANEL MEETINGS. EPA stated in their NOTICE in the Federal Register (FR Vol. 68, No. 24 / Wednesday, February 5, 2003 / Notices/ page 5873) that
"EPA’s current assessment of asbestos toxicity is based primarily on an asbestos assessment completed in 1986, and EPA’s assessment has not changed substantially since that time. The 1986 assessment considers all mineral forms of asbestos and all asbestos fiber sizes (i.e., all fibers longer than 5 micrometers) to be of equal carcinogenic potency. However, since 1986, there have been substantial improvements in asbestos measurement techniques and in the understanding of how asbestos exposure contributes to disease. To incorporate the knowledge gained over the last 17 years into the agency’s toxicity assessment for asbestos, EPA oversaw the development of a revised methodology for conducting risk assessments of asbestos. The proposed risk assessment methodology distinguishes between fiber sizes and fiber types in estimating potential health risks related to asbestos exposure."
A peer review expert panel considered the above-mentioned "revised methodology" at the February 2003 workshop and the proceedings and appendices were published May 30, 2003 as EPA Contract Number 68-C-98-148, Work Assignment 2003-05, prepared by Eastern Research Group, Inc.
Because the EPA website is under constant revision and files may become unaccessible, the MAIN BODY OF THE REPORT IS ALSO ARCHIVED HERE
. To access and view the ARCHIVED APPENDICES TO THE REPORT, CLICK HERE.
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The SAB has also in its deliberations made regularly available some additional reviewer and public comments from later in July 2012. Particularly noteworthy are the EPA "Agency Comment" (response) from David Bussard, dated July 24, 2012, on Questions and Clarifications related to SAB July Draft Report, the Comments From (panel member) Dr.Mort Lippmann In Response To Memo from David Bussard , and Public Comments from Dr. Suresh Moolgavkar of Exponent, Inc. both BEFORE an SAB Libby Amphibole Asbestos Review Panel Public Teleconference on July 25, 2012 and afterwards.
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A new COMMENTARY has been published online by the Annals of Occupational Hygiene by Drs. D.W. Berman and B.W. Case, entitled " Overreliance on a single study: There is no real evidence that applying quality criteria to exposure in asbestos epidemiology affects the estimated risk".
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THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY CONVENED ITS SCIENCE ADVISORY BOARD AD HOC ASBESTOS REVIEW PANEL RE "IRIS Toxicological Review of Libby Amphibole Asbestos" IN EARLY FEBRUARY. Some panel members submitted pre-meeting comments, and EPA also published submitted public comments on this page.
EPA HAD ON DECEMBER 23, 2011 ANNOUNCED it's Science Advisory Board Ad Hoc Asbestos Review Panel's MEMBERSHIP and the basis for selection (PDF) for review of the IRIS Assessment for Libby Amphibole Asbestos.
Members of the Libby Amphibole Asbestos Review Panel are also listed HERE.
THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY, ON AUGUST 25, 2011, ANNOUNCED IMPORTANT DEVELOPMENTS WITH RESPECT TO THE "U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002C, 2011."
The relevant page from EPA's Integrated Risk Information System (IRIS) with links to relevant documents may be accessed by clicking HERE.
In so doing, EPA has performed several important actions:
1. The DRAFT DOCUMENT from August 2011 (which is not to be cited or quoted)regarding a TOXICOLOGICAL REVIEW OF LIBBY AMPHIBOLE ASBESTOS, which is "an assessment of the noncancer and cancer health effects associated with the inhalation route of exposure only", is published as a downloadable PDF file.
It is important to note that this document is "...a preliminary draft for review purposes only...distributed solely for the purpose of predissemination peer review under applicable information quality guidelines".
2. Simultaneously, EPA "announces the release of the IRIS Toxicological Review of Libby Amphibole Asbestos (External Review Draft) for public viewing and comment". This DRAFT is open to Public Comment for 60 days. The deadline for comments is October 24, 2011. In the interim, EPA offers to hold a "public listening session" regarding the draft in Arlington, VA, on October 6, 2011, beginning at 1 p.m. and ending at 5 p.m., Eastern Daylight Time, or when the last presentation has been completed. Those attending may simply "listen" or may make presentations of up to 30 minutes duration. My understanding of the notice is that if NO such presentations are requested THE SESSION WILL BE CANCELLED. Full details as to attendance and/ or submission of presentations (which must occur by September 29, 2011) are provided in a COMPANION FEDERAL REGISTER NOTICE.
3. Simultaneously, EPA releases a draft NCEA Proposed Draft Charge to External Reviewers for the IRIS Toxicological Review of Libby Amphibole Asbestos. It is not clear from the NOTICE whether this DRAFT is also open to Public Comment for 60 days. The CHARGE QUESTIONS will presumably be considered by the Ad Hoc Panel (of External Reviewers) that is being formed for the EPA Science Advisory Board (SAB) on the subject of the IRIS Assessment for Libby Amphibole Asbestos. Announcement of the membership of this committee has not, to my knowledge, been made, but the public comment period regarding NOMINATED PERSONS (CLICK HERE) has ended. (The announcement for nomination was made on May 27, 2011; nominations were accepted until June 17, 2011, and the Public Comment Period on nominees began August 9 and was closed August 30, 2011.
4. Finally, it should be noted that the new (AUGUST 2011) U.S. EPA. IRIS Toxicological Review of Libby Amphibole Asbestos (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/002C, 2011 should not be confused with the earlier document issued in May of 2011. In the interim EPA received comments and advice from other US agencies. EPA has published responses to these comments in association with release of the latest Draft.
Interested observers in Libby and elsewhere should watch the EPA SAB website for further news of the Ad Hoc Panel considerations, which will presumably also be followed by further internal EPA review and public comment period(s).
All of the above is based on my own understanding of the EPA process; document links are provided as a courtesy to readers and are best accessed from the relevant US Government websites directly, as changes are always possible.
A NEW SERIES OF ARTICLES ON "MODE OF ACTION" OF "ASBESTOS" AND OTHER TOPICS
was moved online to the new TAYLOR AND FRANCIS WEBSITE JUNE 2011, with open access, in Journal of Toxicology and Environmental Health, Part B: Critical Reviews.
The journal publishes a series of critical reviews of "asbestos", with the goal of informing on the mode of action of asbestos and determining data gaps and research needs in the field. Process for the production of these papers began with a Workshop held in November of 2009 in Chapel Hill, NC of the National Institute for Environmental Health Sciences (NIEHS). The workshop was supported by NIEHS, National Toxicology Program, U.S. Environmental Protection Agency (Office of Research and Development, Office of Solid Waste and Emergency Response), and the Centers for Disease Control and Prevention (Agency for Toxics Substances and Disease Registry, National Institute for Occupational Safety and Health). It should be noted that all findings are those of the authors and do not necessarily represent the views of the NIEHS or the other sponsoring government agencies.
One article by this author and colleagues Jerrold Abraham, Greg Meeker, Fred Pooley, and Kent Pinkerton discusses
ways in which definitions of “Asbestos” apply to environmental and “low-dose” exposure levels and health effects, with an emphasis on malignant mesothelioma.
********************************************************
On June 13, 2011, a group of Canadian and International organizations and scientists released a letter to Prime Minister Stephen Harper of Canada urging the Canadian Government to support the listing of chrysotile asbestos in the PIC (Prior Informed Consent) List under the Rotterdam Convention, at the Meeting of the Parties to that Convention in June of 2011. Per the letter, the purpose of the Rotterdam Convention is to bring about responsible trade of hazardous substances by requiring that exporting countries obtain “prior informed consent” before shipping substances, which are on the Convention’s list, to another country. The letter is available here.
UPDATE: According to the Toronto Globe and Mail and Reuters this effort has failed, not for the first time. It is only to be hoped that at the 2013 meeting the government will come to its senses and allow the listing. This has been the position of our Research Community in Canada for some time now.
**************************************************************
HEALTH CANADA has made the Chrysotile Asbestos Consensus Statement and Summary
available to "members of the public". It does not yet appear on the HC website. As a great deal of misinformation has been in the popular press about this report you can read it here and judge for yourself.
My own impression: It basically follows (and compares) the findings of three studies; that of Hodgson and Darnton (Ann Occup Hygiene 2000) and the two (published since the Panel report was written) of Berman and Crump, namely
A meta-analysis of asbestos-related cancer risk that addresses fiber size and mineral type and
Update of potency factors for asbestos-related lung cancer and mesothelioma
The Panel report has the usual and inevitable watered-down quality of any "consensus" statement that involves a small (six people) group of people with, in the words of Panel Chair Trevor Ogden, "...members who in the past have expressed strongly opposed views on this subject". It is nevertheless a solid achievement, and should have been published long ago.
Dr. Ogden in his cover letter (see report) also notes re the panel members that "Thanks are due to them for their willingness to work to find a common position as far as possible. Getting them to participate at fairly short notice was itself a significant achievement, for which Dr. Michel Camus and Health Canada staff deserve major credit".
It should also be noted that this is NOT a "Health Canada Report" per se; the title page disclaims:
"This report was written by the Chair and members of the Expert Panel, and the opinions
expressed therein do not necessarily reflect the views of Health Canada".
Again quoting the Chair,
"The Panel supported the approach of two major reviews, which give information on the relationship of the cancers to chrysotile exposure. Generally these show a strong relationship of exposure with lung cancer, but a much less certain relationship with mesothelioma. However, the Consensus Statement and Summary should be consulted for details".
RECENT PUBLICATION ON MESOTHELIOMA RISK IN TWO AMERICAN COUNTIES
We (myself and Dr. Jerrold Abraham) have recently published following peer review and presentation at Inhaled Particles X Heterogeneity of exposure and attribution of mesothelioma: Trends and strategies in two American counties, using lung-retained fiber as an exposure index. This was possible in human mesothelioma cases in Jefferson Parish, Louisiana, where there is an ongoing mesothelioma epidemic - by absolute numbers, the most serious in North America - due to previous manufacturing (epecially at the Johns Manville cement pipe plant there); past shipyard exposures; and especially the practice of the Johns Manville plant of distributing crocidolite-laden scrap to be used in driveways, roads, daycares, schoolyards, etc. all over the neighborhoods of six cities in the county. A map of a small fraction of the sites involved, not all of which were remediated, may be found in the textbook Asbestos and its Diseases edited by Craighead and Gibbs (on page 81).
The other county is of course El Dorado County, California, where risk which has long been suspected is confirmed by the analysis of dog lungs from the area (since publication we have at our lab in Montreal also found that there are no fibers at all in the lungs of control dogs).
TALC, CONTINUED:
In their most recent meeting for a new monograph (Volume 93), IARC assessed among other chemicals "non-asbestiform talc". While the monograph may not be available for some time, a brief summary has been posted online by IARC in pdf format. The principal finding was that "Inhaled talc not containing asbestos or asbestiform fibres is not classifiable as to its carcinogenicity to humans (Group 3). A separate assessment however was made for "Perineal use of talc-based body powder", considered on the strength of the evidence to be "possibly carcinogenic to humans (Group 2B)". Finally, none of this applies of course to talc which IS ASBESTIFORM (which does not mean that the talc CONTAINS asbestos); IARC notes that for example "Mineral talc is usually platy but may also occur as asbestiform fibres...Asbestiform talc must not be confused with talc that contains asbestos... Together with platy talc, asbestiform talc is found in the Gouverneur District of New York State, USA, and occasionally elsewhere; it may be associated with other minerals as observed by transmission electron microscopy".
For further discussion of New York State Gouverneur District abestiform talc and its consequences, please click and read the paper from Dr. Abraham (SUNY Syracuse) and myself entitled Mesothelioma among Workers in Asbestiform Fiber-bearing Talc Mines in New York State published in the Annals of Occupational Hygiene in 2002.
A2006 paper indexed on PUBMED on the Mineralogical and exposure determinants of pulmonary fibrosis among Quebec chrysotile miners and millers has been published in the March 2006 issue of Int Arch Occup Environ Health.
ABSTRACT:
Nayebzadeh A, Case BW, Masse J, Dufresne A. Mineralogical and exposure determinants of pulmonary fibrosis among Quebec chrysotile miners and millers. Int Arch Occup Environ Health 2006 Mar;79(3):227-36.
Objectives: Lung fibre content was determined for 86 former chrysotile miners and millers in two Quebec mining regions: Thetford mines (TM) and the Asbestos region (AR).
Methods: Fibres were assessed using transmission electron microscopy (TEM) and energy dispersive X-ray spectrometry (EDS). Asbestos body (AB) concentrations were assessed by microscopy of tissue digests. Corresponding histological lung tissue sections were quantitatively graded for the severity of interstitial fibrosis on a 12-point scale. Fibrosis score and its associations with (1) fibre concentrations and fibre dimensions within three fibre length intervals (less than 5 um, 5-10 um, and over 10 um), and (2) several exposure variables were evaluated using correlation coefficients and regression techniques.
Results: Concentration of short (<5 um) tremolite fibres was the best predictor of fibrosis grade in both mining groups (r=0.44, P<0.01 and r=0.39, P<0.01 for TM and AR, respectively). Chrysotile fibre concentration showed a lower correlation with the fibrosis grade for subjects from TM only. Long (>10 um) amosite fibre concentration showed a linear relationship with the fibrosis score in miners and millers from AR. Exposure variables, including smoking, had no predictive value for fibrosis grade. Within fibre length categories, fibre dimension was not related to the fibrosis score.
Conclusion: Lung fibre concentration as measured by TEM/EDS, especially that of short (<5 um) tremolite fibres, is a better predictor of fibrosis grade in these two groups of chrysotile miners than either the concentration of ABs or the duration of exposure. Due to the limitation of our counting method, almost all fibres longer than 10 um observed in this study were shorter than 14 um. Thus, if length plays a role in fibrogenesis, it may be related to fibres of greater length than those covered in this study.
PMID: 16283364 [PubMed - in process]
The SITUATION IN EL DORADO COUNTY, CALFORNIA regarding environmental tremolite exposure is receiving increasing scientific and public health attention. The November issue of ENVIRONMENTAL HEALTH PERSPECTIVES contains an article noting the considerable risk there. See
SHOWDOWN IN EL DORADO
; also you can watch video of recent news coverage by CBS; click here or go to the CBS video search page; search for ASBESTOS and click the item "playing with asbestos".
EPA has reported the results of an active air sampling done in the area in October of 2004. Results were criticized by a mining industry lobby group based on a report from their consultant R.J. Lee. These have been addressed with devastating accuracy and comprehensive detail by the April 20, 2006 Response to the November 2005 National Stone, Sand & Gravel Association Report Prepared by the R.J. Lee Group, Inc “Evaluation of EPA’s Analytical Data from the El Dorado Hills Asbestos Evaluation Project”
Discussion of the issues is beyond the scope here, but essentially the arguments boil down to the "cleavage fragments versus asbestos fibres" issue which has been extant since at least 1990, when the ATS Official Statement on Tremolite was issued (relevant portions highlighted; and 1992, when OSHA deregulated "nonasbestiform" tremolite, anthophyllite, and actinolite. The debate on the issues continues, with an EPA expert panel on which this writer served again disputing the OSHA findings in May 2003.
The relevant portion of the panel report for EPA is archived HERE.
Most recently EPA had been criticized by their own IG in regards to Libby, Montana amphibole exposure for inadequate characterization. An interesting article that describes this and related issues was recently published in ENVIRONMENTAL SCIENCE & TECHNOLOGY
by Rebecca Renner.
Getting back to El Dorado County itself, all parties agree that the asbestiform variant of tremolite
occurs in western El Dorado county (and indeed on the western slope of the Sierras). Our own presentation of lung-retained tremolite fibres in area pets (see below) was presented at the American Thoracic Society in San Diego. It was published on page A818 of the Abstract Volume (Supplement to the April number of volume 171) of the American Journal of Respiratory and Critical Care Medicine. You can click here to see a copy. A link to the study has been posted on the El Dorado Hills, Naturally Occurring Asbestos EPA WebSite for Region 9.
Many recent newspaper articles on the subject have also appeared in the Sacramento Bee and elsewhere (you will have to register with the site and search for stories about "asbestos").
The important point is made vis-a-vis Libby Montana - the risk in terms at least of numbers of cases of future mesothelioma seems much greater in Western El Dorado County, based on the larger population there.
The risk in Libby and in El Dorado can be estimated by reference to McDonald et al. (Occupational and Environmental Medicine 2004;61:363-366) as follows:
"over a lifetime of, say, 50 years, an ambient exposure level of 0.1 f/ml would imply under this model an excess risk of 3.2% in all-cause mortality (RR=1.032)— a not insignificant impact. Exposures of this magnitude may indeed be relevant to the residents of Libby, Montana and perhaps even in some construction areas in northern California".
The SUMMARY of the data prepared for presentation on DOG LUNG TREMOLITE FIBER CONTENT from animals living in El Dorado County, California, made available recently at the EPA-sponsored conference on August 18, 2004, by our McGill lab and Dr. Jerrold Abraham's SUNY Syracuse lab is available HERE as a PDF format file.
A new Official Statement of the American Thoracic Society
titled Diagnosis and Initial Management of Nonmalignant Diseases Related to Asbestos
has been released and published in the American Journal of Respiratory and Critical Care Medicine. This Statement, which replaces the 1986 ATS statement and has been worked on by the authors since 2001, deals with diagnosis and management of non-malignant diseases only. It has been much awaited and has already engendered much discussion among interested scientists. Unlike previous ATS statements on this topic, it is rather vague in actual disease definition, although retaing the 1982 1982 College of American Pathologists PATHOLOGIC definition of "asbestosis". You can access the report at the http://www.thoracic.org website of the ATS CLICKING HERE.
A NEW SERIES OF ARTICLES ON "MODE OF ACTION" OF "ASBESTOS" AND OTHER TOPICS
was moved online to the new TAYLOR AND FRANCIS WEBSITE JUNE 2011, with open access, in Journal of Toxicology and Environmental Health, Part B: Critical Reviews.********************************************************
On June 13, 2011, a group of Canadian and International organizations and scientists released a letter to Prime Minister Stephen Harper of Canada urging the Canadian Government to support the listing of chrysotile asbestos in the PIC (Prior Informed Consent) List under the Rotterdam Convention, at the Meeting of the Parties to that Convention in June of 2011. Per the letter, the purpose of the Rotterdam Convention is to bring about responsible trade of hazardous substances by requiring that exporting countries obtain “prior informed consent” before shipping substances, which are on the Convention’s list, to another country. The letter is available here.
UPDATE: According to the Toronto Globe and Mail and Reuters this effort has failed, not for the first time. It is only to be hoped that at the 2013 meeting the government will come to its senses and allow the listing. This has been the position of our Research Community in Canada for some time now.
**************************************************************
HEALTH CANADA has made the
available to "members of the public". It does not yet appear on the HC website. As a great deal of misinformation has been in the popular press about this report you can read it here and judge for yourself.
My own impression: It basically follows (and compares) the findings of three studies; that of Hodgson and Darnton (Ann Occup Hygiene 2000) and the two (published since the Panel report was written) of Berman and Crump, namely
A meta-analysis of asbestos-related cancer risk that addresses fiber size and mineral type and
Update of potency factors for asbestos-related lung cancer and mesothelioma
The Panel report has the usual and inevitable watered-down quality of any "consensus" statement that involves a small (six people) group of people with, in the words of Panel Chair Trevor Ogden, "...members who in the past have expressed strongly opposed views on this subject". It is nevertheless a solid achievement, and should have been published long ago.
Dr. Ogden in his cover letter (see report) also notes re the panel members that "Thanks are due to them for their willingness to work to find a common position as far as possible. Getting them to participate at fairly short notice was itself a significant achievement, for which Dr. Michel Camus and Health Canada staff deserve major credit".
It should also be noted that this is NOT a "Health Canada Report" per se; the title page disclaims:
"This report was written by the Chair and members of the Expert Panel, and the opinions
expressed therein do not necessarily reflect the views of Health Canada".
Again quoting the Chair,
"The Panel supported the approach of two major reviews, which give information on the relationship of the cancers to chrysotile exposure. Generally these show a strong relationship of exposure with lung cancer, but a much less certain relationship with mesothelioma. However, the Consensus Statement and Summary should be consulted for details".
RECENT PUBLICATION ON MESOTHELIOMA RISK IN TWO AMERICAN COUNTIES
We (myself and Dr. Jerrold Abraham) have recently published following peer review and presentation at Inhaled Particles X Heterogeneity of exposure and attribution of mesothelioma: Trends and strategies in two American counties, using lung-retained fiber as an exposure index. This was possible in human mesothelioma cases in Jefferson Parish, Louisiana, where there is an ongoing mesothelioma epidemic - by absolute numbers, the most serious in North America - due to previous manufacturing (epecially at the Johns Manville cement pipe plant there); past shipyard exposures; and especially the practice of the Johns Manville plant of distributing crocidolite-laden scrap to be used in driveways, roads, daycares, schoolyards, etc. all over the neighborhoods of six cities in the county. A map of a small fraction of the sites involved, not all of which were remediated, may be found in the textbook Asbestos and its Diseases edited by Craighead and Gibbs (on page 81).
The other county is of course El Dorado County, California, where risk which has long been suspected is confirmed by the analysis of dog lungs from the area (since publication we have at our lab in Montreal also found that there are no fibers at all in the lungs of control dogs).
For further discussion of New York State Gouverneur District abestiform talc and its consequences, please click and read the paper from Dr. Abraham (SUNY Syracuse) and myself entitled Mesothelioma among Workers in Asbestiform Fiber-bearing Talc Mines in New York State published in the Annals of Occupational Hygiene in 2002.
A2006 paper indexed on PUBMED on the Mineralogical and exposure determinants of pulmonary fibrosis among Quebec chrysotile miners and millers has been published in the March 2006 issue of Int Arch Occup Environ Health.
ABSTRACT:
Nayebzadeh A, Case BW, Masse J, Dufresne A. Mineralogical and exposure determinants of pulmonary fibrosis among Quebec chrysotile miners and millers. Int Arch Occup Environ Health 2006 Mar;79(3):227-36.
Objectives: Lung fibre content was determined for 86 former chrysotile miners and millers in two Quebec mining regions: Thetford mines (TM) and the Asbestos region (AR).
Methods: Fibres were assessed using transmission electron microscopy (TEM) and energy dispersive X-ray spectrometry (EDS). Asbestos body (AB) concentrations were assessed by microscopy of tissue digests. Corresponding histological lung tissue sections were quantitatively graded for the severity of interstitial fibrosis on a 12-point scale. Fibrosis score and its associations with (1) fibre concentrations and fibre dimensions within three fibre length intervals (less than 5 um, 5-10 um, and over 10 um), and (2) several exposure variables were evaluated using correlation coefficients and regression techniques.
Results: Concentration of short (<5 um) tremolite fibres was the best predictor of fibrosis grade in both mining groups (r=0.44, P<0.01 and r=0.39, P<0.01 for TM and AR, respectively). Chrysotile fibre concentration showed a lower correlation with the fibrosis grade for subjects from TM only. Long (>10 um) amosite fibre concentration showed a linear relationship with the fibrosis score in miners and millers from AR. Exposure variables, including smoking, had no predictive value for fibrosis grade. Within fibre length categories, fibre dimension was not related to the fibrosis score.
Conclusion: Lung fibre concentration as measured by TEM/EDS, especially that of short (<5 um) tremolite fibres, is a better predictor of fibrosis grade in these two groups of chrysotile miners than either the concentration of ABs or the duration of exposure. Due to the limitation of our counting method, almost all fibres longer than 10 um observed in this study were shorter than 14 um. Thus, if length plays a role in fibrogenesis, it may be related to fibres of greater length than those covered in this study.
PMID: 16283364 [PubMed - in process]
Chrysotile Asbestos Consensus Statement and Summary
TALC, CONTINUED:
In their most recent meeting for a new monograph (Volume 93), IARC assessed among other chemicals "non-asbestiform talc". While the monograph may not be available for some time, a brief summary has been posted online by IARC in pdf format. The principal finding was that "Inhaled talc not containing asbestos or asbestiform fibres is not classifiable as to its carcinogenicity to humans (Group 3). A separate assessment however was made for "Perineal use of talc-based body powder", considered on the strength of the evidence to be "possibly carcinogenic to humans (Group 2B)". Finally, none of this applies of course to talc which IS ASBESTIFORM (which does not mean that the talc CONTAINS asbestos); IARC notes that for example "Mineral talc is usually platy but may also occur as asbestiform fibres...Asbestiform talc must not be confused with talc that contains asbestos... Together with platy talc, asbestiform talc is found in the Gouverneur District of New York State, USA, and occasionally elsewhere; it may be associated with other minerals as observed by transmission electron microscopy".
The SITUATION IN EL DORADO COUNTY, CALFORNIA regarding environmental tremolite exposure is receiving increasing scientific and public health attention. The November issue of ENVIRONMENTAL HEALTH PERSPECTIVES contains an article noting the considerable risk there. See
SHOWDOWN IN EL DORADO
EPA has reported the results of an active air sampling done in the area in October of 2004. Results were criticized by a mining industry lobby group based on a report from their consultant R.J. Lee. These have been addressed with devastating accuracy and comprehensive detail by the April 20, 2006 Response to the November 2005 National Stone, Sand & Gravel Association Report Prepared by the R.J. Lee Group, Inc “Evaluation of EPA’s Analytical Data from the El Dorado Hills Asbestos Evaluation Project”
Discussion of the issues is beyond the scope here, but essentially the arguments boil down to the "cleavage fragments versus asbestos fibres" issue which has been extant since at least 1990, when the ATS Official Statement on Tremolite was issued (relevant portions highlighted; and 1992, when OSHA deregulated "nonasbestiform" tremolite, anthophyllite, and actinolite. The debate on the issues continues, with an EPA expert panel on which this writer served again disputing the OSHA findings in May 2003.
The relevant portion of the panel report for EPA is archived HERE.
Most recently EPA had been criticized by their own IG in regards to Libby, Montana amphibole exposure for inadequate characterization. An interesting article that describes this and related issues was recently published in ENVIRONMENTAL SCIENCE & TECHNOLOGY by Rebecca Renner.
Getting back to El Dorado County itself, all parties agree that the asbestiform variant of tremolite
occurs in western El Dorado county (and indeed on the western slope of the Sierras). Our own presentation of lung-retained tremolite fibres in area pets (see below) was presented at the American Thoracic Society in San Diego. It was published on page A818 of the Abstract Volume (Supplement to the April number of volume 171) of the American Journal of Respiratory and Critical Care Medicine. You can click here to see a copy. A link to the study has been posted on the El Dorado Hills, Naturally Occurring Asbestos EPA WebSite for Region 9.Many recent newspaper articles on the subject have also appeared in the Sacramento Bee and elsewhere (you will have to register with the site and search for stories about "asbestos").
The important point is made vis-a-vis Libby Montana - the risk in terms at least of numbers of cases of future mesothelioma seems much greater in Western El Dorado County, based on the larger population there.
The risk in Libby and in El Dorado can be estimated by reference to McDonald et al. (Occupational and Environmental Medicine 2004;61:363-366) as follows:
"over a lifetime of, say, 50 years, an ambient exposure level of 0.1 f/ml would imply under this model an excess risk of 3.2% in all-cause mortality (RR=1.032)— a not insignificant impact. Exposures of this magnitude may indeed be relevant to the residents of Libby, Montana and perhaps even in some construction areas in northern California".
The SUMMARY of the data prepared for presentation on DOG LUNG TREMOLITE FIBER CONTENT from animals living in El Dorado County, California, made available recently at the EPA-sponsored conference on August 18, 2004, by our McGill lab and Dr. Jerrold Abraham's SUNY Syracuse lab is available HERE as a PDF format file.
A new Official Statement of the American Thoracic Society
titled Diagnosis and Initial Management of Nonmalignant Diseases Related to AsbestosThe 1990 statement on HEALTH EFFECTS OF TREMOLITE is archived here; currently an ATS EOH committee is working on a NEW tremolite report.
RECENT ASBESTOS REPORTS COMMISSIONED BY GOVERNMENT AGENCIES
The Quebec National Institute of Public Health (INSPQ) has released two separate reports, both in French initially and then in English at a later date.
INSPQ on their web site offers the following summary rationale for the production and issuance of these reports:
In 1997, in light of international developments with respect to asbestos, particularly after its banning in France, Quebec’s ministère de la Santé et des Services sociaux (department of health and social services) set up a Comité aviseur sur l’amiante (asbestos advisory committee). The aim of this committee was to make recommendations about appropriate measures to inform the public and to protect public health in relation to the asbestos situation in Quebec. The advisory committee then created two sub-committees: the first to document asbestos exposure and the second to examine the epidemiology of asbestos-related diseases in Quebec. The sub-committee on exposure was mandated to assess the pertinence and the feasibility of assessing asbestos exposure in the general population, particularly in public buildings such as schools. The sub-committee on epidemiology was mandated to review epidemiological studies available in Quebec on mesothelioma, pulmonary cancers, and asbestosis; evaluate the trends of these diseases; compare data from Quebec to those of other regions; and summarize current scientific knowledge on the effects of asbestos on health. Each sub-committee produced a report, the summaries and recommendations of which are presented here.
The ENGLISH PUBLICATIONS PAGE of the INSPQ has an ENGLISH TRANSLATION OF A SUMMARY OF THESE TWO REPORTS .
FULL English translations of both the Epidemiology Report
and the Report of the Sub-committee on Exposure titled
PLEASE NOTE: This material is copyright ASBESTOS FIBRES IN INDOOR AND OUTDOOR AIR - THE SITUATION IN QUEBEC have now been published.
Please note as well that ONLY translations obtained from INSPQ are official
, and any other translation is unacceptable and unlawful; use of the official INSPQ documents and official INSPQ translations should be governed by the copyright notices within the publications, each of which bears an ISBN publication number."EPA’s current assessment of asbestos toxicity is based primarily on an asbestos assessment completed in 1986, and EPA’s assessment has not changed substantially since that time. The 1986 assessment considers all mineral forms of asbestos and all asbestos fiber sizes (i.e., all fibers longer than 5 micrometers) to be of equal carcinogenic potency. However, since 1986, there have been substantial improvements in asbestos measurement techniques and in the understanding of how asbestos exposure contributes to disease. To incorporate the knowledge gained over the last 17 years into the agency’s toxicity assessment for asbestos, EPA oversaw the development of a revised methodology for conducting risk assessments of asbestos. The proposed risk assessment methodology distinguishes between fiber sizes and fiber types in estimating potential health risks related to asbestos exposure."
From June 12-13 2003, EPA held a separate Asbestos Mechanisms of Toxicity Workshop
in Chicago, Illinois. According to EPA, "The purpose of the workshop was to discuss the molecular induction of asbestos related disease, lung/pleural pathogenesis, and the extrapolation of a dose response relationship". See the website for details and documents posted. A summary report "documented areas of general agreement among the panelists or areas where a clear consensus did not exist".
McGill School of Environment:
Year 2000 Undergraduate Student Project on Magnola Magnesium plant at Asbestos, Quebec
Year 2002 Undergraduate Student Project 
Year 2008 Undergraduate Student Project on Biological and Social Impacts of Naturally Occurring Asbestos (NOA) in El Dorado County, California