A review of available sources identified rat acute toxicity data for inhalation and oral 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 inhalation data did not report deaths or adverse toxic effects, so it was determined inappropriate for TEEL development (Section 3.3.1); 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.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LD50 (>2000 mg/kg)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was rat LCLo data not found during this review; instead, the current TEEL-3 basis is a rat oral LD50, resulting in significantly less conservative values. The Rev. 29A TEEL-2/TEEL-1 values used the same methodology (Table 3.5), with differences due to the change in TEEL-3.