DIETHYLAMINE

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: 109-89-7; CHEMICAL FORMULA: (C₂H₅)₂NH

OSHA’s previous limit for diethylamine was 25 ppm as an 8-hour TWA. The Agency proposed to lower this limit to an 8-hour TWA of 10 ppm and to add a 15-minute STEL of 25 ppm, based on the ACGIH (1986/Ex. 1-3) recommendation. NIOSH (Ex. 8-47, Table N1) concurred with these proposed limits, which are established in the final rule. Diethylamine is a colorless liquid with an ammonia-like odor.

Diethylamine is a strong irritant of the eyes, skin, and mucous membranes, and chronic sublethal exposures cause tracheitis, bronchitis, pneumonitis, and pulmonary edema (ACGIH 1986/Ex. 1-3, p. 197). In rabbits, the dermal LD(50) is 0.82 ml/kg, and instillation of solutions of 1 percent or greater into the eyes of rabbits caused corneal opacity (Sutton 1963/Ex. 1-1101). Direct contact of the skin with diethylamine causes necrosis (ACGIH 1986/Ex. 1-3, p. 197). Rabbits exposed seven hours/day, five days/week for six weeks to 50 or 100 ppm diethylamine survived; those exposed to 50 ppm showed marked lung and corneal irritation, and, occasionally, degeneration of the heart muscle (Brieger and Hodes 1951/Ex. 1-408). In the animals exposed to 100 ppm, these changes were more severe, and the parenchymatous degeneration of the heart muscle was marked (Brieger and Hodes 1951/Ex. 1-408).

OSHA finds that its previous limit of 25 ppm as an 8-hour TWA is only one-half the level found to cause marked lung and corneal irritation in animals exposed for six weeks. The Agency concludes that the 25-ppm limit is not sufficient to protect workers from the significant risk of skin burns, corneal injury, pulmonary irritation, and skin, eye, and upper respiratory tract irritation potentially associated with more prolonged exposures to this substance. OSHA considers the exposure-related effects of diethylamine on the eyes, skin, and respiratory tract to be material impairments of health. To afford workers greater protection from these adverse effects, OSHA is revising its limit for diethylamine to 10 ppm as an 8-hour TWA and 25 ppm as a 15-minute STEL; these limits are established in the final rule.