Metropolitan Life Insurance Company, Report on a Dust Survey of the Manville Plant (1929)

An undated, unsigned typed report, with photographs of the work rooms, on a study of dust conditions at Johns-Manville's Manville, New Jersey, plant made in October and November 1929. It calls itself "the first unit in a series of such studies" of the asbestos industry in the United States and Canada, planned by the Industrial Health Service of the Metropolitan Life Insurance Company to learn whether asbestos dust harmed workers, with physical examinations and laboratory work "probably at Saranac" (Saranac Laboratory) to follow. Most counts were below the U.S. Public Health Service limit of 10,000,000 particles per cubic foot set for silica dust, and the report found "the probability of asbestosis, so called, is remote." But counts at the pipe-covering saws and the refractory cement mixers were "excessive," reaching 44,700,000 particles per cubic foot where dry refractory cement was bagged.

What it shows

The report explains that compensation "has been claimed and allowed in several cases of so-called asbestosis" in the United States and that "the industry is desirous of learning whether this disease is a true occupational hazard." It cautioned that the silica limit might not fit asbestos, since much longer fibers had been found in lung tissue, and that "we are not justified in accepting this standard as final." It also recorded exhaust pipes "either disconnected or blocked," no lockers, and that "No effort is made to prevent workers from expectorating on the floors." Metropolitan Life went on to survey Raybestos-Manhattan's plants in 1930 (Charleston plant, 1930), and the study was published in 1935 (Lanza, McConnell and Fehnel).

In Johns-Manville's chronology

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

Comprehensive dust count at J-M by Metropolitan Life, 11/29. Highest exposures were found at asbestos cement bagging and pipe cover sawing operations. Dust control measures slated first for these operations.

Editor's note: J-M's description names asbestos cement bagging and pipe-cover sawing as the highest exposures. The report's highest counts are at refractory cement bagging and mixing and at the saw-slitting of pipe covering, and the report does not say dust control was slated first for these operations.