C. L. Sheckler, Summary of Atmospheric Hygiene Studies at the Manville Plant (1957–1959)

An 18-page confidential set of dust-count tables for Johns-Manville's Manville, New Jersey, plant, initialed by C. L. Sheckler of the plant's Safety Department. A summary page counts the sampling done department by department: 1,778 counts at 649 stations from June 1957 to December 1958, and 1,764 counts at 530 stations from December 1958 to June 1959. The pages that follow list each sampling station (machines, saws, dust collectors, carton sealing, floor sweeping) in pipe covering, Thermobestos, Transite pipe, textiles, packings, friction materials, rock wool, shingles and other departments, with particle counts, asbestos fiber counts, and an asterisk on "Stations requiring control."

What it shows

By 1958 J-M was measuring both total dust particles and asbestos fibers at hundreds of points in its largest plant, and marking the stations above the "maximum allowable concentration." A note on the summary says sample analysis by J-M's own industrial hygiene laboratory began July 1, 1958. The tables show that a number of stations, especially at dust collectors and some saws and mills, were flagged as needing control. The standards J-M applied are set out in its 1958 Manual of Standard Practices.

In Johns-Manville's chronology

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

Confidential summary of Atmospheric Hygiene Studies Manville plant, dust counts June 1957 through June 1959 by location and job operation (including saws, finishing, carton sealing). Some third-party type tasks measure average counts above 5 mppcf. (Received from U.S. for Goldfield deposition.)