H. M. Jackson on Dr. Enterline's Study, "Mortality Patterns of a Group of Retired Asbestos Workers" (1971)

A two-page confidential memo of February 17, 1971, from H. M. Jackson at J-M headquarters to J. B. Jobe, F. H. May and A. B. Marchant, copied to Dr. G. W. Wright and Dr. T. H. Davison, sending them "Mortality Patterns of a Group of Retired Asbestos Workers." The 145-page report, dated December 1970, is by Pierre Decoufle under the direction of Dr. Philip E. Enterline of the University of Pittsburgh's School of Public Health, done under a J-M contract begun May 1, 1968. It followed 1,200 men who retired from J-M's U.S. and Canadian asbestos products plants from 1941 to 1966 and found that their lung cancer death rate was "two and one-half times" that of U.S. white men.

What it shows

The report found excess deaths from lung cancer, digestive cancers and respiratory disease, the last entirely from pneumoconiosis and lung fibrosis. Production workers had about 7% more lung cancer than expected, but men who had worked mainly in maintenance and service jobs had a "four-fold risk," and men with the highest dust exposure scores a five-fold excess. Jackson's memo urges caution: the men started at J-M at an average age of 39.8, the exposure estimates before the last ten years were rough, and the data did not reflect improved dust control. But he notes that the high risk among maintenance-service men "raises question concerning the import of intermittent but possibly high, short duration exposures," which J-M's dust surveys had not measured. These were J-M's own retirees, studied at the company's expense; Enterline's further findings in March pointed the same way.

In Johns-Manville's chronology

Johns-Manville's own chronology of what the company knew describes this document as follows:

"Mortality Patterns of a Group of Retired Asbestos Workers," begun in 1968: cohort retired prior to 1/1/68, age 65 minimum, estimates of levels of individual dust exposure were based on actual counts from 1958-1968 and rough approximations prior to those years. Data raised questions "concerning the import of intermittent but possibly high, short duration exposures" since high risk to maintenance-service employees was shown. Jackson memorandum of 2/17/71 to Jobe, May, Marchant, Wright, Davison.