A review of available sources identified acute toxicity data (LD50) for various species (rat, rabbit) 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 most preferred species and route data, rat oral LD50, was selected as the TEEL-3 basis. It was reported in units of µL/kg; therefore, it was converted to mg/kg using the reported density at 25°C (1.09 g/mL). TEEL-1 and TEEL-2 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 (6170 µL/kg x 1.09 g/mL = 6725.3 mg/kg
This review generated a PAC-3 value consistent with Rev. 29A and PAC-2 and PAC-1 values inconsistent. The Rev. 29A and current TEEL-3 sources and methodologies are consistent. The Rev. 29A TEEL-2 basis was a rat TCLo not found during the current review; instead, the current TEEL-2 is derived from the TEEL-3 (Table 3.5). The Rev. 29A and current TEEL-1 use the same methodology, with differences due to the change in TEEL-2.