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: 142-64-3; Chemical Formula: C4H10N2•2HCl

Previously, OSHA had no limit for piperazine dihydrochloride. The ACGIH recommends a TLV-TWA limit of 5 mg/m3. The proposed PEL was an 8-hour TWA of 5 mg/m3; NIOSH (Ex. 8-47) concurred with the proposed PEL, and this limit is established in the final rule. Piperazine dihydrochloride is a solid.

Piperazine dihydrochloride is a water-soluble solid with low systemic toxicity and mild irritant properties; the compound is biologically active. The oral LD(50) for rats has been reported as 4.9 g/kg (NIOSH 1984, as cited in ACGIH 1986/Ex. 1-3, p. 491).

Eye and skin irritation have been reported as a result of human exposures to high (not further specified) levels of piperazine dihydrochloride; subjects experienced mild to moderate skin burns and sensitization. Inhalation of the dust has been associated with asthmatic reactions (Dow Chemical Company 1977h, as cited in ACGIH 1986/Ex. 1-3, p. 491). OSHA received no comments other than that from NIOSH (Ex. 8-47) on this substance.

In the final rule, OSHA is establishing a limit of 5 mg/m3 as an 8-hour TWA for piperazine dihydrochloride. The Agency concludes that this limit will reduce the significant risks of sensitization and eye and skin irritation, which constitute material health impairments and are potentially associated with exposures to this substance at levels above the new limit.

Page last reviewed: September 28, 2011