Dr. A. J. Lanza, Memorandum on the Control of Pneumoconiosis Due to Diatomaceous Earth (1951)

A five-page memorandum of September 5, 1951, by Dr. A. J. Lanza of the New York University-Bellevue Institute of Industrial Medicine, sent to J. P. Woodard and H. M. Jackson of Johns-Manville and to doctors at the Lompoc diatomaceous earth plant. Lanza and Jackson had checked the examination records of 617 Lompoc employees for 1948 to mid-1950: 191 were negative, 246 were classed P-1, 136 P-2 and 44 P-3, and 15 cases showed "massive shadows." Lanza wrote that no one knew the safe exposure limit for diatomaceous earth, and that the accepted five million particle standard for crystalline silica "has no scientific warranty" and rested on clinical observation. He urged that dust control be supplemented by aluminum therapy, the inhaling of aluminum powder then used against silicosis.

What it shows

Lanza judged the negative, P-1 and P-2 men free of symptoms and said the P-3 cases had some symptoms but were mostly still working. He described the Saranac Laboratory animal experiments then under way on diatomaceous earth and aluminum, and argued for trying aluminum on the workers without waiting: if the program had "little or no merit, no harm is done," and the industry's position would be helped. His proposed steps included presenting the program to union officials and to employees through Industrial Relations. The memo shows that by 1951 J-M had X-ray evidence of lung changes in a large share of its Lompoc workforce, and that its consultant doubted the dust standard it relied on. Lanza's later correspondence with J-M on X-ray readings is in his July 1951 letter to Dr. Pauly.

In Johns-Manville's chronology

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

Dr. Lanza writes a memorandum regarding the control of pneumoconiosis due to diatomaceous earth, 9/5/51. He states that at Lompoc, out of 617 workers, 246 have a P1 classification, 136 have a P2 classification, and 44 have a P3 classification. He states that it is not known what the proper TLV is for diatomaceous earth, and the present TLV is based on clinical observation. Therefore, consideration should be given to supplementing dust control with other measures of prevention such as aluminum therapy.