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The morbidity and mortality of vermiculite miners and millers exposed to tremolite‐actinolite: Part II. Mortality
Author(s) -
Amandus H. E.,
Wheeler R.
Publication year - 1987
Publication title -
american journal of industrial medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 104
eISSN - 1097-0274
pISSN - 0271-3586
DOI - 10.1002/ajim.4700110103
Subject(s) - tremolite , medicine , lung cancer , vermiculite , actinolite , mortality rate , population , asbestos , demography , surgery , environmental health , composite material , materials science , quartz , chlorite , epidote , sociology
The vermiculite ore and concentrate of a mine and mill located near Libby, Montana was found to be contaminated with a fiber of the tremolite/actinolite series. A study was conducted to estimate the exposure‐response relationship for mortality for 575 men who had been hired prior to 1970 and employed at least 1 year at the Montana site. Individual cumulative fiber exposure (fiber‐years) was calculated. Results indicated that mortality from nonmalignant respiratory disease (NMRD) and lung cancer was significantly increased compared to the U.S. white male population. For those workers more than 20 years since hire, the standard mortality rate (SMR) for lung cancer (ICDA 162–163) was 84.7, 225.1, 109.3, and 671.3 for less than 50, 50–99, 100–399, and more than 399 fiber‐years respectively. Corresponding results for NMRD (ICDA 460–519) were 327.8, 283.5, 0, and 278.4. Based on a linear model for greater than 20 years since hire, the estimated percentage increase in lung cancer mortality risk was 0.6% for each fiber‐year of exposure. At 5 fiber‐years, the estimated percentage was 2.9% from an unrestricted (nonthreshold) linear model and 0.6% from a survival model.