A review of available sources identified the following: LD50 (mouse and rat) acute toxicity data for intraperitoneal and oral routes. Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were subsequently down 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, an oral mouse LD50 data was selected as the TEEL-3 basis. TEEL-2 or TEEL-1 values were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Mouse oral LD50 (1760 mg/kg)
This review generated TEEL values that are inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a rat intraperitoneal LD50, while the current basis is a more preferred route (oral > intraperitoneal, Section 3.3.2). The Rev. 29A and current TEEL-2 and TEEL-1 were derived using the same methodology, with differences due to the change in TEEL-3.