DICHLOROETHYL ETHER

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: 111-44-4; Chemical Formula: (ClCH₂CH₂)₂O

OSHA previously had a 15-ppm ceiling limit, with a skin notation, for dichloroethyl ether. The Agency proposed to revise its limit for dichloroethyl ether to 5 ppm as an 8-hour TWA, with a 10-ppm STEL, and to retain the skin notation. NIOSH (Ex. 8-47, Table N6A; Tr. pp. 3-96 to 3-97) concurred with the proposed limits but indicated that a carcinogen designation should be added to the PEL. The final rule establishes the proposed limits, which are consistent with the ACGIH recommendation. Dichloroethyl ether is a colorless, flammable liquid with a nauseating odor.

The primary health hazards associated with exposure to this substance are irritation of the eyes and respiratory system and pulmonary damage. Schrenk, Patty, and Yant (1933/Ex. 1-665) reported that guinea pigs exposed to the vapor of dichloroethyl ether at 500 ppm experienced immediate and severe eye and nose irritation, respiratory disturbances after 1.5 to 3 hours, and death after five to eight hours. Lung, kidney, liver, and brain damage were also observed in these animals; exposure to a reduced level of 105 ppm caused eventual death after 10 hours of continuous exposure. A one-hour exposure to 105 ppm caused irritation only (Carpenter, Smyth, and Pozzani 1949/Ex. 1-722). At 35 ppm, for an unspecified duration, irritation but no other adverse effects were observed (Schrenk, Patty, and Yant 1933/Ex. 1-665). Rats responded similarly, with four-hour exposures to 250 ppm proving lethal (Carpenter, Smyth, and Pozzani 1949/Ex. 1-722).

Repeated exposures to 69 ppm (seven hours/day, five days/week for 130 days) caused no serious injury in rats or guinea pigs; only mild stress-related effects were noted (Kosyan 1967/Ex. 1-914). However, other studies of guinea pigs have shown mild primary irritative effects on the skin, and fatalities occurred when 300 mg/kg was applied dermally as a pure liquid for 24 hours (Smyth and Carpenter 1948/Ex. 1-375). Direct contact of dichloroethyl ether with the eye causes moderate pain, conjunctival irritation, and transient corneal injury (Carpenter and Smyth 1946/Ex. 1-859). A sufficient amount of dichloroethyl ether can be absorbed through the skin to be lethal: Sax and Lewis (Dangerous Properties of Industrial Materials, 7th ed., 1989) report the dermal LD(50) in rabbits as 720 mg/kg. Mice have been reported to develop hepatomas after prolonged oral administration (80 weeks) of dichloroethyl ether at 300 mg/kg (Innes, Ulland, Valerio et al. 1969/Ex. 1-270).

Humans exposed briefly to dichloroethyl ether at concentrations above 550 ppm experienced intolerable eye and nasal irritation, with coughing, nausea, and retching. Concentrations between 100 and 260 ppm were irritating but tolerable; however, the odor of dichloroethyl ether was still nauseating at 35 ppm (Schrenk, Patty, and Yant 1933/ Ex. 1-665). Eye irritation has been reported from industrial exposure to a concentration of dichloroethyl ether of 2.5 ppm (Bell and Jones 1958/Ex. 1-714). A single fatality, presumably from inhalation of the vapor, has been reported but not documented (Elkins 1959c, as cited in ACGIH 1986/Ex. 1-3, p. 186). NIOSH submitted the only comments on OSHA’s proposed revision of the PEL for dichloroethyl ether.

In the final rule, OSHA is establishing a 5 ppm TWA and 10 ppm STEL for this substance. The Agency concludes that a 5-ppm TWA and a 10-ppm STEL will protect workers against the significant risk of irritation, lung injury, and nausea associated with occupational exposure to elevated levels of dichloroethyl ether, and these limits are established in the final rule. OSHA considers the eye and nasal irritation, lung injury, and other symptoms associated with exposure to dichloroethyl ether to be material impairments of health and functional capacity. The skin notation is retained because dichloroethyl ether can cause systemic toxicity if percutaneously absorbed.