Confirmation of Chrysotile Hazard
For decades, asbestos stakeholders have emulated the discredited practices of tobacco companies in their attempt to protect the image of their product. Just as scientists commissioned by the tobacco companies issued pronouncements that smoking had not been proved to cause lung cancer, so “researchers” paid by the asbestos lobby continue to deny that exposure to chrysotile asbestos causes fatal diseases. Despite industry's best efforts to create confusion and forestall asbestos bans, independent scientists and international agencies continue to detail the horrific consequences of human exposure to chrysotile.
On March 11, 2009, the paper: Lung Cancer Mortality and Fiber Exposures among North Carolina Asbestos Textile Workers,1 was published online. The research detailed in this work provides “further evidence that exposure to chrysotile asbestos in textile manufacturing is associated with increased risk of lung cancer, asbestosis, cancer of the pleura and mesothelioma.” A follow-up of 5,770 workers reveals that mortality from all causes, including cancer, was higher than expected. There were elevated standardized mortality ratios for pleural cancer, mesothelioma and pneumoconiosis; the risk of asbestosis and lung cancer rose with cumulative fiber exposure. Contained within the discussion section of this 30-page paper is the statement:
“This study provides evidence that workers exposed to chrysotile are at increased risk of mesothelioma, as well as lung cancer. The number of mesothelioma deaths recorded in other studies of workers exposed only to chrysotile has been small, suggesting a hypothesis that chrysotile does not cause mesothelioma. However, we observed an SMR of approximately 11 for mesothelioma based on 4 deaths observed and 0.37 expected after mesothelioma began to be coded as a separate cause of death in 1999 with the 10th revision of the ICD. In every case when mesothelioma was mentioned on the death certificate of a worker in the cohort, it was coded as the underlying cause of death. Mesothelioma is believed to have been underreported in the early years of this study, however, so it is possible that additional cases before 1999 were missed.”
From March 17-24, 2009 the International Agency for Research on Cancer (IARC) Monographs Secretariat held a meeting on the: Evaluation of Carcinogenic Risks to Humans2 in Lyons, France. Colleagues who attended this meeting confirmed the following findings:
- there is sufficient evidence that all forms of asbestos (actinolite, amosite, anthophyllite, chrysotile, crocidolite, tremolite) cause mesothelioma as well as lung, laryngeal and ovarian cancers in humans. There is sufficient evidence in animals to show that all forms of asbestos cause lung cancer and mesothelioma.
- There is limited evidence that asbestos exposure causes pharynx cancer, stomach cancer and gastrointestinal (GI) cancers. The evidence on GI cancers was the strongest of these three and the Working Group vote was evenly split between limited and sufficient evidence for this site.
Since 1987, all forms of asbestos have been classified as carcinogenic to humans by the IARC. On June 30, 2008 at The XVIII World Congress on Safety and Health at Work in Korea, IARC Spokesperson Dr. Kurt Straif said there was absolutely no doubt that occupational and environmental exposure to all asbestos can cause mesothelioma, lung cancer and asbestos; evidence has also linked asbestos exposure to laryngeal cancer.3 In his paper, The Carcinogenicity of Asbestos – Evaluations by IARC and WHO, Recent Developments and Global Burden of Asbestos-Related Cancer, Dr. Straif noted:
“Mesotheliomas have been observed after occupational exposure to crocidolite, amosite, tremolite and chrysotile, as well as among the general population living in the neighbourhood of asbestos factories and mines and in people living with asbestos workers… no threshold has been identified for the carcinogenic risk of chrysotile… Urgent and concerted action is needed, particularly in developing countries to curtail a second, even bigger wave of the global asbestos disaster.”4
April 3, 2009
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1 Loomis D, Dement JM, Wolf SH, Richardson DB. Lung Cancer Mortality and Fiber Exposures among North Carolina Asbestos Textile Workers, Occupational and Environmental Medicine, published online March 11, 2009 by the BMJ Publishing Group Ltd.
2 Volume 100, Meeting C: Metals, Particles and Fibres. A list of participants can be accessed at:
http://monographs.iarc.fr/ENG/Meetings/100C-ListParticipants.pdf
3 Kazan-Allen L. Consensus on Asbestos Hazard. August 16, 2008.
http://ibasecretariat.org/lka_glob_consensus_asb_haz.php
4 Straif K. The Carcinogenicity of Asbestos – Evaluations by IARC and WHO, Recent Developments and Global Burden of Asbestos-Related Cancer. Abstract SY02-07 of paper presented during Symposia: Asbestos – A Global Disaster in Seoul, Korea. Page 28-29, Collection of Conference Abstracts of The XVIII World Congress on Safety and Health at Work.
