A review of available sources identified the following: LC50 and LD¬50 (mouse, rat) acute toxicity data. 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 3.6.2, 3.6.3, 3.6.4 and evaluated using factors in Tables 3.2, 3.3, and 3.4. The most preferred route, a 10-minute mouse LC50, was selected as the TEEL-3 basis and it was scaled to 60-minute equivalent using the ten Berge equation (Section 3.3.4). ¬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 = Mouse LC50 (18 mg/m3/10 min)
This review generated less conservative TEEL values than those reported in Rev. 29A. The Rev. 29A TEEL-3 basis was a rat intraperitoneal LD50, which is a less preferred route than the current basis (LC50 > LD50, Table 3.1). The Rev. 29A TEEL-2 basis was a mouse TDLo not found in the current review; instead, the TEEL-2 was derived from the TEEL-3 (Table 3.5). The Rev. 29A and current TEEL-1 values were derived using the same methodology, with differences due to the change in TEEL-2.