TETRASODIUM PYROPHOSPHATE

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: 7722-88-5; Chemical Formula: Na₄P₂O₇

The OSHA Z tables previously included no limit for tetrasodium pyrophosphate. OSHA proposed a PEL of 5 mg/m³ as an 8-hour TWA, and NIOSH (Ex. 8-47, Table N1) concurred with OSHA’s proposed limit for this substance. This limit is established in the final rule and is consistent with the ACGIH recommendation. Tetrasodium pyrophosphate may occur as either a white powder or a crystalline substance.

Tetrasodium pyrophosphate is an alkaline dust and therefore causes irritation to the eyes and the respiratory tract (ACGIH 1986/Ex. 1-3, p. 567). For this reason, the ACGIH recommended a time-weighted average TLV of 5 mg/m³, which is one-half the value recommended for irritant dusts. NIOSH’s comment was the only one submitted on OSHA’s proposal to issue a 5-mg/m³ 8-hour TWA for this substance.

The Agency concludes that this previously unregulated chemical poses a significant risk of eye and respiratory tract irritation to workers potentially exposed to high concentrations. OSHA has determined that these irritant effects represent material impairments of health. Accordingly, OSHA is promulgating a 5-mg/m³ 8-hour TWA limit for tetrasodium pyrophosphate in the final rule.