n-PROPYL ACETATE

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: 109-60-4; Chemical Formula: CH₃COOCH₂CH₂CH₃

OSHA previously had an 8-hour TWA limit of 200 ppm for n-propyl acetate. The ACGIH also has a 200-ppm TWA limit but adds a TLV-STEL of 250 ppm. The proposal retained the 8-hour TWA PEL of 200 ppm for n-propyl acetate and added a 15-minute STEL of 250 ppm. NIOSH (Ex. 8-47, Table N1) concurs that these limits are appropriate, and they are established by the final rule. n-Propyl acetate is a pleasant-smelling liquid.

The primary health effects associated with exposure to n-propyl acetate are narcosis and eye and respiratory irritation. The five-hour narcotic concentrations for cats and mice have been reported as 9000 ppm and 6000 ppm, respectively (Flury and Wirth 1933, as cited in ACGIH 1986/Ex. 1-3, p. 500). n-Propyl acetate’s narcotic action is 1.3 times that of ethyl acetate; salivation and irritation of cats’ eyes occurred at 2600 ppm (Flury and Wirth 1933, as cited in ACGIH 1986/Ex. 1-3, p. 500). A four-hour exposure at 8000 ppm killed four of six rats (Smyth 1964, as cited in ACGIH 1986/Ex. 1-3, p. 500). Only NIOSH commented on n-propyl acetate.

n-Propyl acetate appears to be more toxic than isopropyl acetate or ethyl acetate but less so than n-butyl acetate (ACGIH 1986, p. 500).

In the final rule, OSHA is retaining the 8-hour TWA PEL of 200 ppm for n-propyl acetate and adding a STEL of 250 ppm. The Agency concludes that both of these limits are required to prevent the significant risk of narcosis and eye and respiratory tract irritation, which are material impairments of health that are associated with exposures to levels above the 8-hour TWA limit alone.