One Hundred Years of Federal Mining Safety and Health Research

worker had evidence of silicosis among the 1,133 workers who began working in the granite
sheds after engineering controls were begun in 1937.
4.1.2 The Uranium Mining Study
The study of uranium miners was initiated by the Public Health Service because it was expected
that long exposure to radon would cause an elevated rate of lung cancer among these miners.
This long-term study was started in 1950, when uranium mining was a relatively new segment of
the U.S. mining industry. By 1963, an increased lung cancer incidence was evident among these
uranium miners.
Early in the investigation, a tentative standard of 1 Working Level had been recommended. A
Working Level (WL) was a combination of alpha-emitting products equivalent to 100 picocuries
per liter of air. By 1969, data indicated that of the 6,000 men who had been uranium miners, an
estimated 600 to 1,100 would die of lung cancer within the next 20 years because of radiation
exposure on the job.
Most of the research in uranium was conducted by the Western Area Occupational Health
Laboratory in Salt Lake City. The Public Health Service Division of Occupational Health
recommended a standard of 0.3 WL for underground mines. This recommendation of 0.3 WL
was later promulgated as a standard by the Bureau and the Department of Labor.
4.1.3 Coal Miner Health Studies
In 1926, the Governor of Pennsylvania and the United Mine Workers labor union asked the
Public Health Service to undertake a study of coal miners’ asthma. This investigation was
conducted between 1928 and 1931 among the anthracite miners of eastern Pennsylvania by the
Office of Industrial Hygiene and Sanitation of the Public Health Service. It was the first major
epidemiologic study of chest diseases of coal miners in the United States.
Before the American study was completed, British investigators published findings that included
a pathologic description of coal workers’ lung disease that they called anthracosilicosis. The
Public Health Service investigation determined that 23 percent of 2,711 miners examined had
evidence of anthracosilicosis and suggested 25 MPPCF of coal mine dust as the recommended
safe exposure. Studies by the Bureau in 1969 determined that 25 MPPCF of coal mine dust was
about the equivalent of 2 mg/m 3 , a value that was to become the legal standard in the Federal
Coal Mine Health and Safety Act of 1969.
While recognizing a distinct disease entity in the anthracite coal mining population, many
American investigators, prior to 1952, assumed that bituminous coal did not produce a disabling
pneumoconiosis. There was a general belief that the pneumoconiosis reported by investigators
was due primarily to the quartz content of the coal and was actually a type of silicosis.
Coal workers’ pneumoconiosis (CWP) was recognized as a specific disease entity in about 1936
in Great Britain, when extensive studies were initiated by the Medical Research Council. The
first studies of the health of bituminous coal miners in the United States began about 1941. The
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