A review of available sources identified acute toxicity data for following various routes (inhalation, intraperitoneal, oral) and species (mouse, rat). 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. Inhalation exposures were scaled to 60-minute equivalents using the ten Berge equation (Section 3.3.4). The most preferred route and species toxicity data, a rat LCLo, was selected as the TEEL-3 basis. TEEL-2 and TEEL-1 values were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat LCLo (18 mg/m3/4H)
This review generated TEEL values that are lower than those in Rev. 29A. The Rev. 29A TEEL-3 basis, a 120-minute mouse LC50, was not found during the review; instead, the current TEEL-3 basis is a 4-hour rat LCLo. The Rev. 29A and current TEEL-2 and TEEL-1 methodology used are consistent, with differences due to the change in TEEL-3.