FLUORINE

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: 7782-41-4; Chemical Formula: F

OSHA’s current PEL for fluorine is 0.1 ppm; NIOSH has no REL for fluorine. In 1973, the ACGIH revised its TLV to 1 ppm and, subsequent to that change, adopted a TLV-STEL of 2 ppm. OSHA proposed these ACGIH limits of 1 ppm TWA and 2 ppm STEL; however, the final rule retains the Agency’s existing 0.1 ppm TWA limit. Fluorine is a pale yellow gas with a pungent irritating odor.

The ACGIH’s previous 0.1 ppm TLV, which was adopted by OSHA in 1971, was based on a 30-day inhalation study in rats and dogs (Stokinger 1949b, as cited in ACGIH 1986/Ex. 1-3, p. 274) in which no consistent pulmonary, renal, or blood effects were observed following exposure to 0.5 ppm. The ACGIH believed that a TLV of 0.1 ppm would “provide a working environment of probable safety from the effects of F2” (ACGIH 1966/ Ex. 1-13). Subsequently, the ACGIH reviewed a seven-year study (Lyon 1962/Ex. 1-639) of 61 workers exposed to fluorine concentrations “far in excess of 0.1 ppm” (ACGIH 1986/Ex. 1-3, p. 2274), which reported a lack of significant medical findings. This evidence, along with more recent animal evidence (Keplinger and Suissa 1968/Ex. 1-342) suggesting that animals were not as sensitive to fluorine as was reported by Stokinger (1949b, as cited in ACGIH 1986/Ex. 1-3, p. 274), led the ACGIH to increase its TLV to 1 ppm. The STEL of 2 ppm was supported by a study (Ricca 1970/Ex. 1-357) in which human volunteers repeatedly exposed to 10 ppm reported only slight irritation.

NIOSH (Ex. 8-47, Table N2) submitted extensive comments to the record criticizing the ACGIH’s reasoning in raising the limit for fluorine. NIOSH concluded:

• [T]here is no data existing to support raising the limit. The Lyon (1962/Ex. 1-639) study is severely limited and a review of the actual paper indicates [that] it has far less value than reported in the ACGIH documentation. All the animal data is, in fact, consistent with the original exposure data on which the 0.1 ppm level was based Ex. 8-47, p. 3).

OSHA agrees with NIOSH and has determined that it is not appropriate, as had originally been proposed by the Agency, to increase the limit for fluorine at this time. OSHA concludes that the human and animal evidence is inadequate to support an increase in the 8-hour TWA for this substance from 0.1 ppm to 1 ppm. OSHA is therefore retaining its PEL of 0.1 ppm as an 8-hour TWA.