A review of available sources identified acute toxicity data (LC50, LDLo, TDLo) for several species and routes. In addition, analysts evaluated exposure limits (IDLH (1990 & 1994), TLV-TWA) for the elemental component fluorides (as F) (CASRN: varies). Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were selected according to type of exposure, species, and route according to the hierarchies stated in Sections 3.3.1, 3.3.2, and evaluated using factors in Tables 3.2, 3.3, and 3.4. The IDLH (1990 & 1994) for fluorides (as F) were evaluated as the TEEL-3 basis; however, there are no acute inhalation data to base these limits on, and they are therefore based on acute oral toxicity data in humans. As such, the most preferred exposure data, a rat LC50, was selected as the TEEL-3 basis and scaled to a 60-minute equivalent using the ten Berge equation (Section 3.3.4). The lowest reported human (female) oral TDLo, with toxicity endpoints of cyanosis of the lungs/thorax or respiration, was selected as the TEEL-2 basis. The TLV-TWA for fluorides (as F) was evaluated as the TEEL-1 basis but yielded a TEEL-1 > TEEL-2; therefore, it was not selected for TEEL development. The TEEL-1 value was derived according to Table 3.5.
• PAC-1 = TEEL-1 = TEEL-2/11
• PAC-2 = TEEL-2 = Human (female) oral TDLo (7 mg/kg; Endpoints: cyanosis of lungs, thorax, or respiration)
• PAC-3 = TEEL-3 = Rat LC50 (1 mg/L/4H)
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A TEEL bases were derived using MW-adjusted TLV-TWA for fluorides for TEEL-1, a rat oral TDLo for TEEL-2, and MW-adjusted IDLH (1990) as fluorides for TEEL-3. Instead, the current review selected a 4-hour rat LC50 as the TEEL-3 basis, a human (female) oral TDLo as the TEEL-2 basis, and derived TEEL-1 from the TEEL-2 (Section 3.4.2).