G. L. Swallow to J-M Plant Managers on Counting Stations at the TLV as Under It (1971)

A one-page memo of October 1, 1971, from G. L. Swallow of J-M's Environmental Control Department to its division production managers and plant managers, on industrial hygiene survey reports. Until then, he wrote, any station "at or over TLV was unacceptable and required corrective action." Because the new federal rules spoke of exposures "above" the threshold limit values, "starting immediately, stations at but not over TLV will be considered as being under TLV."

What it shows

The memo loosened J-M's own internal rule: a work station measured exactly at the threshold limit value, which had called for corrective action, would now be reported as acceptable. Copies went to H. M. Jackson and C. L. Sheckler at headquarters and to the area industrial hygienists.

In Johns-Manville's chronology

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

G.L. Swallow (10/1/71) states that the interpretation of TLV has been that any station at or over TLV is unacceptable and requires corrective action. With the publication of the new OSHA rules and regulations, concentrations above TLV now shall be avoided. "In view of this wording in the Federal Law, starting immediately, stations at but not over TLV will be considered as being under TLV."