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Federal Register / Vol. 51; No. 119 / Friday. June 20, 1986 / Rules and Regulations
oncology. Only 9 percent of lung cancer asbestos exposure and may develop
patients survive for 5 or more years after within 10-20 years after the initial
diagnosis (American Cancer Society, Ex. exposure. Plaques are opaque patches
64rl8Q). Asbestos exposure acts
visible on chest X rays that consist of
synergistically with cigarette smoking to dense strands of collagen fconnective
multiply the risk or developing lung
tissue protein) lined by mesothelial
cancer.
cells. All commercially used types of
Many studies have also shown -
asbestos induce plaques. Plaques can
conclusively that mesothelioma is
occur without Fibrosis and do not seem
associated with asbestos exposure. In
to reflect the severity of pulmonary
some asbestos-exposed occupational
parenchymal disease. Pleural
groups, 10-18.percent of deaths have
calcification is also commonly found in
been attributable to malignant mesotheliomas. Malignant
persons who have been exposed to asbestos (Craighead et al.. Ex. 84-033).
mesotheliomas of the pleura and
The adverse effects of exposure to
peritoneum are extremely rare in
asbestos have been observed in workers
persons not.exposed to asbestos.
involved in the manufacture of asbestos
Generally, a latency period of at least
cement pipes and shingles (Enlerline et
25-30 years is required before
al., Exs. 84-044, 84-122; Weill et al., Ex.
mesotheliomas are observed in an
84-123, Finkelstein, Exs. 84-208, 84-240),
occupational cohort, although some
asbestos mining and milling (Wagner et
victims of mesothelioma have had
al., Ex. 2-21; Liddell et al., Ex. 84-059;
latency periods exceeding 40 years
McDonald et al., Ex. 84-085; Hobbs et
(Craighead el al'., Ex. 84-033). This form al., Ex. 84-072; Nicholson et al. Ex. 84-
of cancer is rarely curable and is usually 086; Rubino et al,, Ex. 84-086), asbestos
fatal within a year after diagnosis.
textile manufacturing (Doll, Ex. 84-040;
Some epidemiologic studies of
Peto et al., Ex. 84-189; Berry et al.. Ex.
asbestos-exposed persons have shown 84-020; Dement et al.. Ex. 84-037),
increases in esophageal, stomach, colo insulation work (Selikoff et al., Ex. 84-
rectal, kidney, laryngeal, pharyngeal,
109). shipbuilding (Selikoff et al., Ex. 84-
and buccal cavity cancers. Although the 091: Blot et al.. ex. 84-109; Tagnon et al.,
increased risk of incurring cancers at
Ex. 84-182), talc mining and milling
these sites is not as great as the
(Brown et al., Ex. 84-29) and in a variety
increased risk of lung cancer and
of asbestos products manufacturing
mesothelioma, the increase is of .
industries (Jones et al., Ex. 84-138;
considerable importance because.of the Henderson and Enterline, Ex. 84-048;
high background rates, and therefore the McDonald and McDonald; Ex. 84-154;
large number of victims, associated with Seidman et al.. Exs. 84-087; 261-A;
some of these tumors in the general
Robinson et al.. Ex. 84-082; Acheson et
population. For example, a 50 percent
al.. Ex. 84-103):
increase in a common cancer such as
The conclusions just expressed are
colo-rccta! cancer results in many.more widely accepted both in the U.S. and
deaths than a 50 percent increase in a
abroad. The following agencies and
rare cancer.
organizations have reviewed the health
Asbestosis is pulmonary fibrosis -
data for asbestos: International Agency
caused by the accumulation of asbestos . for Research on Cancer (IARC) (Ex. 84-
fibers in the lungs. The adverse effects 321), Organization for Economic
of asbestosis range from shortness of
Cooperation and Development (OECD) .
breath during exertion to cyanosis,
(Ex. 84-337), NIOSH (Exs. 84-338 and
effusions of serous fluid, respiratory
84-320), Advisory Committee of the
failure, cardiac decompensotion. ond'
Health and Safety Commission of the
death. Asbestosis is often a progressive United kingdom (Ex. 84-216), the.
disease, even Inthe absence of
Chronic Hazard Advisory Panel on
continued exposure. The symptoms of
Asbestos (CHAP) (Ex. 84t258), and the
the disease are shorlness.of breath,
, U.S, Environmental Protection Agency
cough, fa tigue, and vague feelings of
(Ex. 84-180). All of these groups have,
sickness: When the fibrosis worsens,
concluded that there is a causal
shortness of breath occurs even at rest. relationship between asbestos exposure
One clinical feature of early asbestosis and the development of cancer and non-
as well as other lung diseases is end-
malignant respiratory disease. NIOSH
inspiratory crackles (rales). Diagnosis of recommended reducing the permissible
asbestosis is based on the presence of
exposure limit (PEL) for asbestos to 0.1
characteristic'radiologic changes,
fiber per cubic centimeter (0.1 f/cc) in
symptoms, rales, other clinical features of Fibrosing lung disease, and a history
1976. In 1980, a joint NIOSH-OSHA Asbestos Work Group stated that there
of exposure to asbestos. Asbestos exposure can cause pleurul '
and/or other pulmonary disease. Pleural plaques are one of the markers of
was no level of exposure to asbestos . below which clinical effects did not occur and recommended a PEL of 0.1 fiber per cubic centimeter (0.1f/cc),
based on the limitations of current technologies for measuring airborne concentrations of asbestos. The 1979 report of the Advisory Committee of the Health and Safety Commission of the United Kingdom (hereafter referred to as the U.K: Committee] led to the reduction of the British standard for asbestos to 1 f/cc for chrysotile, 0.5 f/cc for amcslte. and 0.2 f/cc for crocidolite.
The following sections describe the record evidence that demonstrates the causal relationship between asbestos exposure and increased riskB of incurring lung cancer, mesothelioma, gastrointestinal cancer, and nonmalignant respiratory diseases such as asbestosis. In addition, evidence is presented pertaining to the relationship between exposure to various types and sizes of asbestos Fiber and the risks of asbestos-related disease; evidence concerning the synergistic effect of smoking and asbestos exposure on the risks of developing lung cancer is also presented. Most of the health effects evidence was previously presented in OSHA's November proposal (48 FR 51099-51122). The current publication summarizes the evidence contained in that Federal Register notice and presents in detail new evidence obtained during and after the public hearing.
B. Epidemiologic Evidence of Risk of Lung Cancer and Mesothelioma Mortality
1. Epidemiologic Studies
The epidemiologic studies of greatest interest are those that show a correlation between the intensity and duration of asbestos exposure and an observed excess in lung cancer and mesothelioma. In the November proposal, OSHA reviewed several studies that provided information on exposure level and incidence of lung cancer (Exs. 84-^21:84-38; 84-37; 84-48; 84-87; 84-90; 84-208: 84-240) and mesothelioma (Exs. 84-30; 84-87; 84-90; 84-208: 84-240); These studies; which provide the basis for OSHA's . Quantitative Risk Assessment are briefly reviewed here, along with a number of more recent investigations (Exs. 182-C; 163-E; 168-A; 188^B; 261-A) that were submitted to the record after publication of the November proposal.
Seidman et al. (Ex. 84-087) studied cause specific mortality among 820 amosite insulation manufacturing workers employed sometime during 1941-1945 at the Patterson insulation facility, which was known to have a deficientventilation system. Estimates of asbestos exposure at this facility
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