Document 7MMnzqz96zeBBymwG9803K8EE

On I. T. Hodgson and A. Damton < Table 11. (continued) Fibre Mesothelioma Lung cancer Risk summaries for. cumulative exposures of 0.005 CfmLyr and lower At these levels only mesothelioma need be considered. The absolute risk is low--, but quantitative uncertainties'are very considerable. Crocidoliie Best estimate about 10 deaths per 100 000 exposed. Highest arguable estimate 55, Insignificant, possibly zero lowest. Best estimate fulls to insignificant level at 0.0002 f/ml.yr, and highest arguable risk becomes insignificant at 6x10"" f/ml.yr Amositc Best estimate about 2 deaths per IOGUOO exposed Itigltesi arguable lifetime risk 15, falling to <1 (ie. insignificant) at 7x'IO's Oml.yr Chrysolite Insignificant Insigniticanl, very possihJy zero `Exposure assumed to be accumulated over short--up to 5 yr periods storting ul age 50. Eur exposure at ullicr ages adjust llie predicted mesnihclioiiui figures using llic factors in 'lahle 9. Estimates for longer periods of exposure can be approximated by making separate estimates for successive S-year periods and adding llie resulting risks (this will slightly overestimate risk). Estimates have been rounded to nearest 5 in seaxtd significant digit (or to one significant digit wlicn less than 10).' The lung cancer risk Is based on British male mortality in 1997 when 9.5% of male deaths at ages 40*79 were due to lung cancer. This represents an average for a population with a post pattern of smoking simitar to that of older British men. lit 1996 23% of men aged 60+ had never (or only occussionally) smoked, and 25% were current smokers, fur lifetime smokers the lung cancer risk will be about double the stated levels, for non-smokers about a sixth (if the interaction with asbestos is multiplicative) or about a third if the relative risk : X' is higher than in non-smokers as suggested by Berry tt at. (1985). The lung cancer risk arguable in `exceptional circumstances' is derived from the Carolina cohort using a .value of R,. of 2.19 taken from the analysis of Stayncr ci ul. It should only he i r,f considered where there is simultaneous exposure to textile grade (i.e. long fibre) chrysolite and mineral oil or some analogous co-exposure. The simple pro rata formulae proposed in this table do not take account of the impact of competing causes of mortality. The impact will ho trivial so long us lltc predicted asbestos related mortality is low, and limited-far predicted (individual cause) mortality below about 30 pereciu. Above litis level the individual asbestos related diseases (including asbestosis. which is not covered by this analysis) will reduce each other's observed impact. In this situation all that cun usefully be predicted is that total asbestos related mortality will be veryhigh indeed.