GERMANIUM TETRAHYDRIDE

OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.

CAS: 7782-65-2; Chemical Formula: GeH₄

OSHA formerly had no limit for germanium tetrahydride. The ACGIH has a TLV of 0.2 ppm TWA for this colorless gas. The proposed PEL was an 8-hour TWA of 0.2 ppm, with which NIOSH (Ex. 8-47, Table N1) concurs. In the final rule, the 0.2-ppm 8-hour TWA is established as OSHA’s PEL for germanium tetrahydride.

An early study indicated that germanium tetrahydride has a toxicity between that of tin hydride and arsine (Flury and Zernik 1931e/Ex. 1-993). In this study, a rabbit survived exposure to 100 ppm for one hour. One-hour exposures at 150 and 185 ppm caused fatalities in mice, and similar exposures involving guinea pigs resulted in sickness at the 150-ppm level and death at 185 ppm (Flury and Zernik 1931e/Ex. 1-993). On the other hand, Webster (1946/Ex. 1-399) reported that germanium tetrahydride is less toxic than both tin hydride and arsine. The effect of exposure to germanium tetrahydride is hemolysis. Data concerning chronic or subacute toxicities are not available. Based on germanium’s acute toxicity, which is approximately half that of stibine, the ACGIH recommends an 8-hour TLV of 0.2 ppm TWA. OSHA received no comments, other than NIOSH’s, on this substance.

In the final rule, OSHA establishes a PEL of 0.2 ppm as an 8-hour TWA for germanium tetrahydride to reduce the significant risk of hemolytic effects, which constitute material impairments of health that are associated with exposure to this substance at levels above the new PEL. The Agency concludes that implementation of this limit will substantially reduce this significant risk.