Previously, OSHA had no limit for diethyl ketone. The ACGIH has a limit of 200 ppm TWA for this colorless liquid, which has an acetone-like odor. The proposed PEL was 200 ppm as an 8-hour TWA, and NIOSH (Ex. 8-47, Table N1) concurs with this limit, which is established in the final rule.
The oral LD(50) for diethyl ketone in rats is reported to be 2.14 g/kg. Four of six rats died when exposed to diethyl ketone for four hours at 8000 ppm (Smyth, Carpenter, Weil, and Pozzani 1954/Ex. 1-440). In general, the toxicities of the methyl ketones increase with increasing molecular weight; diethyl ketone is somewhat less toxic than is methyl propyl ketone (TLV-TWA of 200 ppm) (NIOSH 1978f, as cited in ACGIH 1986/Ex. 1-3, p. 199). All of the ketones cause mucous membrane and eye and skin irritation. OSHA received no comments on diethyl ketone except those from NIOSH.
In the final rule, OSHA is establishing an 8-hour TWA PEL of 200 ppm for diethyl ketone, the same limit being proposed for methyl propyl ketone. The Agency concludes that this limit will reduce the significant risk of eye and skin irritation, which are material health impairments that are associated with exposure to diethyl ketone at levels above the new PEL.