American Conference of Governmental Industrial Hygienists Adopts Its 1947 Limits, Including Asbestos (1947)

Excerpts from the proceedings of the American Conference of Governmental Industrial Hygienists' ninth annual meeting, held in Buffalo, New York, April 26–29, 1947, with a page from the August 1947 Industrial Hygiene Newsletter. Dr. L. T. Fairhall of the U.S. Public Health Service presented the Committee on Threshold Limits' list of "maximum allowable concentration" values, which the conference accepted. The newsletter's table of "1947 M.A.C. Values" lists asbestos under mineral dusts at 5 million particles per cubic foot of air.

What it shows

Fairhall defined the limit as the amount of a gas, vapor, fume or dust "which can be tolerated by man with no bodily discomfort nor impairment of bodily function, either immediately or after years of exposure." He also said the values were "not permanent values" but subject to yearly revision, and that they had to balance health against "the effect of attaining this value upon the manufacturing operation." The asbestos figure was the one suggested in the U.S. Public Health Service's 1938 Dreessen study. Two months later, an engineer reporting to the asbestos textile industry questioned whether it was safe. The figure later became known as the Threshold Limit Value (TLV) and stayed in use for asbestos until the 1970s (see the ACGIH limits of 1970).

In Johns-Manville's chronology

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

ACGIH (trade association of governmental hygienists) adopts 5 mppcf standard as its recommendation.

Editor's note: J-M's description calls the ACGIH a trade association. It was a professional body of government industrial hygienists.

Related documents

• Dreessen and Others, A Study of Asbestosis in the Asbestos Textile Industry (1938)
• American Conference of Governmental Industrial Hygienists, Threshold Limit Values for 1970, with a Proposed Asbestos Limit of 5 Fibers (1970)