This paper is a reanalysis of data on the respiratory cancer mortality experience of 2,802 men who worked one year or more during the period 1940-1964 at a copper smelter in Tacoma, Washington. Exposure estimates presented earlier have been recalculated and perhaps improved. While the previous analysis showed only a weak relation between respiratory cancer and arsenic exposure, use of new data shows a much stronger relation--but one that is concave downward and not ordinarily considered for environmental exposure and cancer. This new analysis indicates that arsenic is probably more potent as a carcinogen than indicated by other studies. It also demonstrates the distinction between airborne arsenic and the bioavailability of arsenic, and the importance of this distinction for risk assessment. When a dose-response relation is based on airborne concentrations of arsenic, it is clearly concave downward, but when based on urine concentrations, it appears to be linear.

The mortality experience of 1074 white men who retired from a United States asbestos company during the period 1941-67 and who were exposed to asbestos working as production and maintenance employees for the company is reported to the end of 1980 when 88% of this cohort was known to be dead.

No abstract

Objectives-An independent and updated historical cohort mortality study was conducted among chemical plant workers to investigate further an association between exposures to formaldehyde and particulates and cancers of the nasopharynx and lung reported in an earlier National Cancer Institute study of the same plant.

A cohort of 1075 men who completed their working lifetimes with an asbestos company, worked at a facility in the United States, and retired with a company pension during the period 1941--67 was updated for deaths through 1973. The average length of employment was 25 years, and all had been exposed to asbestos dust. Respiratory cancer and pneumoconiosis-pulmonary fibrosis mortalities were examined in relation to cumulative dust exposure and to other factors after taking into account cumulative dust exposure. Men who worked in the production of asbestos cement pipe exhibited a higher risk of respiratory cancer, as did men with some crocidolite asbestos exposure. Because these two groups overlap, we could not be certain that crocidolite asbestos was responsible for the increased risk. Men working in general plant maintenance displayed a striking lack of deaths due to pneumoconiosis-pulmonary fibrosis, as compared with production workers and with maintenance personnel assigned to specific departments. Five mesothelioma deaths were observed at age 65 and over. Three of these deaths occurred during the period 1970--3.