A review of available sources identified acute toxicity data (LC50, LD50, LDLo) for several species and routes. 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 LC50 was evaluated; the dose reported is an “approximate” value, therefore it was not selected for TEEL development. Instead, the rat oral LD50 was selected as the TEEL-3 basis. TEEL-2 and TEEL-1 values were derived according to Table 3.5.
• PAC-1 = TEEL-1 = TEEL-2/11
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = Rat oral LD50 (1900 mg/kg)
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a rat LCLo not identified during the current review; instead, the current TEEL-3 basis is a rat oral LD50. The Rev. 29A and current TEEL-2 and TEEL-1 methodologies are consistent, with differences due to the change in TEEL-3.