A review of available sources identified the following: rat and mouse acute toxicity data (LD50) and exposure limits for tellurium (CASRN: 13494-80-9, TLV-TWA, IDLH). 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 was evaluated as a TEEL-3 basis; however, it was not selected because 1) the IDLH bases did not include tellurates, and 2) there is available acute toxicity data for this chemical. Instead, a rat oral LD50 for sodium tellurate was selected as the TEEL-3 basis. TEEL-2 values were derived according to Table 3.5. The tellurium TLV-TWA was selected as the TEEL-1 basis and a compound adjustment factor was applied (Section 3.2.2).
• TEEL-1 = MW-adjusted TLV-TWA (tellurium, CASRN: 13494-80-9, 0.1 mg/m3) x 3
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LD50 (385 mg/kg)
This review generated TEEL-3 and TEEL-2 values inconsistent with Rev. 29A. The Rev. 29A and current TEEL-1 values, sources, and methodology are consistent. The Rev. 29A TEEL-3 and TEEL-2 were derived from the TEEL-1, while the current TEEL-3 basis is a rat oral LD50¬ for sodium tellurate. Differences in TEEL-2 values is due to the change in TEEL-3.