A review of available sources identified the following: a WEEL-TWA exposure limit, LD50 (rabbit, rat), rat LC50 and rabbit TDLo toxicity data. 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 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 rabbit TDLo reported ataxia as a toxicity endpoint, appropriate for TEEL development, and was selected as the TEEL-2 basis. The WEEL-TWA was selected as the TEEL-1 basis.
• TEEL-1 = WEEL-TWA (10 ppm) x 3
• TEEL-2 = Rabbit subcutaneous, soluble TDLo (>10000 mg/kg; toxic endpoint includes ataxia, a loss of muscle function)
• TEEL-3 = Rat LC50 (36000 mg/m3/4H)
This reviewed generated TEEL-3 and TEEL-1 values consistent with Rev. 29A. The Rev. 29A TEEL-2 basis, a rat TCLo, was not found during the current review; instead, the TEEL-2 was developed from an available rabbit TD¬Lo.