OSHA had no former limit for o-sec-butylphenol. The ACGIH has a 5-ppm 8-hour TLV-TWA, with a skin notation. The proposed PEL was an 8-hour TWA of 5 ppm, with a skin notation; NIOSH (Ex. 8-47, Table N1) concurs with this limit, which is established in the final rule. o-sec-Butylphenol is a colorless liquid.
Animal studies indicate that contact with o-sec-butylphenol causes irritation of the skin, eyes, and respiratory tract, and may result in skin burns. A Dow Chemical Company study (1977i, as cited in ACGIH 1986/Ex. 1-3, p. 84) showed that the oral and skin absorption LD(50)s for guinea pigs ranged between 0.6 and 2.4 g/kg. Prolonged contact of o-sec-butylphenol with the skin of these animals resulted in burns, whereas direct application to the eyes did not cause corneal injury. The oral LD(50) for rats is 2700 mg/kg (Dangerous Properties of Industrial Materials , 6th ed., Sax 1984), and rats exposed to saturated air levels of this chemical survived for seven hours (Dow Chemical Company 1977i, as cited in ACGIH 1986/Ex. 1-3, p. 84). The intravenous LD(50) for mice is 6 mg/kg (Sax 1984). Acute workplace exposures to o-sec-butylphenol have resulted in mild respiratory irritation and skin burns (ACGIH 1986/Ex. 1-3, p. 84).
In the final rule, OSHA is establishing an 8-hour TWA limit of 5 ppm for o-sec-butylphenol, with a skin notation. The Agency concludes that this limit is necessary to protect workers from the significant risks of eye and respiratory tract irritation and skin burns associated with exposure to this substance at the levels formerly permitted by the absence of an OSHA limit. Eye and mucous membrane irritation and skin burns constitute material health impairments within the meaning of the Act.