OSHA had a limit of 200 ppm (8-hour TWA) for n-propyl alcohol. The ACGIH has the same TWA limit but adds a 250-ppm 15-minute STEL and a skin notation. The proposal retained the 200-ppm 8-hour TWA PEL and added a 15-minute STEL of 250 ppm and a skin notation. NIOSH (Ex. 8-47, Table N1) concurs that these limits are appropriate, and they are established in the final rule. The skin notation, however, is not retained (see the discussion on skin notations in Section VI.C.18 of this preamble). Propyl alcohol is a colorless liquid with an alcohol-like odor.
The primary health effect associated with exposure to propyl alcohol is mild narcosis. Propyl alcohol's toxicity is somewhat greater than that of isopropyl alcohol (Gleason, Gosselin, and Hodge 1963/Ex. 1-1034).
The inhalation LD(50) for propyl alcohol in rats is reported as 1.9 g/kg (Smyth, Carpenter, Weil, and Pozzani 1954/Ex. 1-440). Starrek reported deep narcosis in mice inhaling the vapor at a concentration of 4100 ppm for 240 minutes and of 24,500 ppm for 60 minutes; ataxia appeared in 90 to 120 minutes at 3250 ppm (Starrek 1938/Ex. 1-872). These effects are almost twice as intense as those reported for exposure to the vapor of isopropyl alcohol. The dermal LD(50) in rabbits is 5040 mg/kg (Dangerous Properties of Industrial Materials, 6th ed., Sax, 1984).
Nelson, Enge, Ross, and associates (1943/Ex. 1-66) reported mild eye, nose, and throat irritation in humans exposed at 400 ppm to the vapor of isopropyl alcohol, but no data exist on human sensory response to propyl alcohol vapor. The ACGIH (1986/Ex. 1-3, p. 500) reports that many industrial hygienists consider the vapor of propyl alcohol to be more irritating to the throat than the vapor of the isomer.
One comment, other than NIOSH's, was received on isopropyl alcohol. The Motor Vehicle Manufacturers Association (Ex. 3-902) asked that rulemaking for propyl alcohol be delayed, but did not provide any evidence in support of its position.
In the final rule, OSHA is retaining the 8-hour TWA PEL of 200 ppm and adding a STEL of 250 ppm for propyl alcohol; the skin notation is not included in the final rule because the LD(50) in rabbits is 5040 mg/kg, well above the level determined by OSHA to require a skin notation (see Section VI.C.18 for a discussion of skin notations). The Agency concludes that these limits will protect workers against the significant risk of narcosis and irritation, both material impairments of health.