A review of available sources identified a LOC and mouse and rat acute toxicity data (LD50) 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. Analysts selected the most preferred species and route toxicity data, rat oral LD50; this is also the most current (1992). The LOC was evaluated as a TEEL-2 source; however, it would result in a TEEL-2 > TEEL-3. Instead, 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 (10 mg/kg)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a mouse intraperitoneal LD50. This source was found during the review; however, it was reported as a range (100-200 mg/kg) from an older source (1962). Analysts instead selected a more preferred species and route (Section 3.3.2) from a more recent source (Section 3.3.1). The Rev. 29A TEEL-2 was the LOC, which was not selected by analysts because this resulted in a TEEL-2 > TEEL-3. Instead, the TEEL-2 was derived from the TEEL-3 (Table 3.5). The Rev. 29 A and current TEEL-1 use the same methodology, with differences due to the change in TEEL-2.