Document dabbboOwX10rR2m8wZvkZdob6

Federal Register. / Vol. 51. No. 119 / Friday, June 20; I960 / Rules and Regulations 22643 in some cases, dificits. but showed very much lower ratios. Considering that lung cancer is increasing in recent years, the ratio between excess Cl cancer to lung cancer would decrease, a value ot 10 percent excess was chosen as a [Ex. 116, p. 2]. Even Dr. Weill, who said he would have preferred OSHA not include quantitative estimates of Cl cancer risk noted that "it doesn't make a lot of difference in my view in terms of reasonable value. It's a relatively small the policy that emerges from such a risk additional contribution. I think it assessment" [Tr. 6/19, p. 1-193]. underestimates what the actual contribution would be |Tr. 8/19. p. 1--115--116). There was some objection to OSHA's quantification of the risk of gastrointestinal cancer (e.g. Ex. 320), the major issue being a lack of an observed dose-response for this type of cancer. Again Dr. Nicholson responded to this objection: Thus. OSHA feels confident in including estimates of risk from gastrointestinal cancer in the final standard; Though this is still some controversy over the inclusion of these estimates in the risk assessment. OSHA believes there is sufficient evidence to support their inclusion and to suggest that their contribution to the overall Welt, we have limited dose-response data. estimates of risk may, in fact, be And it's of two natures. One in terms of increased risk with increased exposure. It would appear that it's a very flat relationship. I've looked at it specifically for insulation, workers, and it turns out that within about 10 understated. The estimates of risk of gastrointestinal cancer are also given in Table 6 along with estimates of lung cancer and mesothelioma risks. years, there appears to be an elevated-risk SO percent above that which would be expected, approximately. And that same elevated risk continues with time among insulators who continue working. * ` * There is a second dose-response relationship that is seen. . . . [l]f one takes The incidence of cancers at sites other than the lung, mesothelium. and gastrointestinal tract have been shown to be elevated in some asbestos exposure studies, including laryngeal, kidney, pharyngeal and buccal cavity those studies in which the number of gastrointestinal cancers either expected of observed exceeds 10. so we're looking at a study that has enough data that It could be-- the results would not be simply statistical variability, and the study shows a statistically significant lung cancer risk so that we're looking at studies that have . cancers. To OSHA, it appears that the excess risk for "other cancerB" is about the same as for gastrointestinal cancers. OSHA recognizes many uncertainties iri quantifying this risk, in view of the inconsistencies in findings among different epidemiologic studies. (Some exposures that are of.slgnificance. one-finds a studies have found excess risk from, fairly reasonable increasing relationship in other cancers, while other studies have the risk of. overall risk, of gastrointestinal not). The sites showing excess risk have cancer with the overall risk of access [excess] lung cancer. That is, access [excess] 'gastrointestinal cancer compared to access : also varied among studies. Therefore. OSHA has not made numerical [excess] lung cancer correlates reasonable estimates of risks for these other well ITr. 8/19. p. 1-113-114). cancers at this time. To the extent that And , while Dr. Schneiderman noted estimates of these cancers are not 'There is no adequate model of included in the overall estimates of risk. digestive cancers", he also stated that OSHA has underestimated the total "OSHA's estimate [for gastrointestinal . cancer risk posed by exposure to cancer risk] appears to be reasonable" asbestos. The data indicating gastrointestinal cancer excesses are stronger and more consistent than the data suggesting excesses at these other cancer sites. Thus, OSHA does not feel compelled to quantify the risk of cancer at these other sites at this time. The high quality and well-supported estimates of the excess risk of lung cancer, mesothelioma: gastrointestinal cancer, and asbestosis alone provide sufficient bases upon which to justify this regulatory action. IV. Estimates of Cancer Mortality The best estimates of Kt and Km were utilized to estimate the mortality from exposures to varying concentrations of asbestos for different time periods. The calculations are age, intensity and duration specific. Table 6 shows the excess asbestos-related mortality rates from lung cancer, mesothelioma, and gastrointestinal cancer (gastrointestinal cancer excess is assumed to be 10% of the lung cancer excess). Table 8 gives the predicted excess lifetime risk of cancer for exposures of one year, 20 years, and 45 years, assuming first exposure at age 25. In these calculations. Equation 1 and Equation 3 were used with values of Kt equal to 0.01 and KM equal to 1 x Mr* and the 1977 U.S. male background lung cancer mortality rates. Because of age-specific increases in lung cancer rates in older men since 1977, estimates based on more recent background rates would be higher. Calculations were done for each 5-year age interval, and then summed lo'give a total lifetime risk. The calculations performed to give the results in Table 6 assumed that the relative risk increased following ten years after onset of exposure and continued to rise until ten years after cessation of exposure, after which it remained constant. GLEASON-000891