A review of available sources identified mouse and acute toxicity data (LD50) for several routes, in additional to indium compounds exposure limits (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 route and species, a rat intraperitoneal LD50, was selected as the TEEL-3 basis. The TEEL-2 value was derived according to Table 3.5. A molecular weight adjusted TWA-TLV was considered as a TEEL-1 basis, but it was not selected because it 1) resulted in a TEEL-1 value greater than the TEEL-2, and 2) may not reflect the corrosive effect of indium trichloride. Instead, the TEEL-1 was derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat intraperitoneal LD50 (2370 µg/kg)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-1 basis was a MW-adjusted indium compounds TLV-TWA (as In), from which the TEEL-2 and TEEL-3 values were derived. The current review selected a rat intraperitoneal LD50 as the TEEL-3 basis, from which the TEEL-2 and TEEL-1 values were derived. These more conservative values are based on acute toxicity for indium trichloride and were thus considered a more accurate estimation of its toxic effects for the purpose of TEEL development. Additionally, note that this chemical also has radioactive counterpart due to Indium (CAS No: 7440-74-6); analysts confirmed that this CASRN is for the non-radioactive compound.