A review of available sources identified acute toxicity data (LD50, LDLo) for several species and routes. In addition, analysts evaluated exposure limits (TWAs) for indium compounds (In, CASRN: 7440-74-6). 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 most preferred species toxicity data, a rat oral LDLo, was selected as the TEEL-3 basis. The TEEL-2 value was derived according to Table 3.5. The TLV-TWA for indium compounds was selected as the TEEL-1 basis and a compound adjustment factor was applied (Section 3.2.2).
• PAC-1 = TEEL-1 = MW-adjusted TLV-TWA (indium compounds, CASRN: 7440-74-6; 0.1 mg/m3) x 3
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = Rat oral LDLo (1200 mg/kg)
This review generated PAC-3 and PAC-2 values inconsistent with Rev. 29A, and a PAC-1 value consistent with Rev. 29A. The Rev. 29A and current TEEL-1 values, source, and methodology are consistent. The Rev. 29A TEEL-3 and TEEL-2 were derived from the TEEL-1. The current TEEL-3 basis is acute toxicity data for indium sulfate (Section 3.1), from which the TEEL-2 was derived (Table 3.5).