Canadian studies

1. M. Camus et al. (Health of women in mining towns)

Studies carried out by Michel Camus of Health Canada on the health of women living in mining towns of Quebec where chrysotile was mined over many decades permitted him to come to surprising conclusions to certain people.

The incidence of pulmonary cancer in women resident in the towns of Asbestos, Thetford Mines and Black Lake is not any higher than the incidence in women living in the 65 reference towns in Quebec. These observations unravel the myth "that a single fibre can kill!". In addition the health risk model for exposure to asbestos dust established by the E.P.A. (American Environmental protection Agency) overestimates the risk by a factor of 10.

Ref. : Camus, M., Siemiatycki, J. , Meek, B. "Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer", New England Journal of Medecine, 338: 1565-1571, 1998.

2. M. Camus (1997) (Risk vs low exposure levels)

In another report published in 1997, under the title "The Risk of Evaluating the Risks Associated, with Low Levels of Asbestos "(Travail et Santé, vol 13, no 1, pages 5-16-17). Michel Camus states that"… we should compare the known risks of asbestos to those of substitute products and estimate if the ratio of these risks is "significantly higher to decide to remove asbestos."

In other works, do the hypothetical benefits of asbestos removal for users or occupants of buildings surpass by a significant margin the exorbitant costs involved?

In conclusion: The quest for "zero" risk though commendable is not realistic and can become dangerous.

3. Studies by the team of J. C. McDonald et al.of McGill University at Montreal.

The incidence of pulmonary disease of mine workers has been reduced to very low levels.

Today, the risks of developing asbestosis or other pulmonary diseases in the chrysotile mines are extremely low due to the very low airborne fibre concentrations at the workplaces.

The authors conclude that below a cumulative exposure level to chrysotile dust of 800 fibres/ml  years (ex : 40 years at  20 fibres/ml), there is no detectable correlation between dust levels and the standardized mortality rates ((S.M.R.) for all causes of deaths including cancers.

"The significance of this study is that we were unable to detect any excess lung cancers in these workers attributable to their work at exposure levels below about 50f/cc. The public should be aware that at current occupational exposure any deaths from asbestosis or lung cancer are most unlikely".

Ref.: Liddel, F. D. K. McDonald, A. D., and McDonald, J. C. (1997), the 1891-1920 birth cohort of Quebec chrysotile miners and millers : development from 1904 and mortality to 1992, Ann. Occup. Hyg. 41 : 13-35.