A review of available sources identified rat and mouse acute toxicity data (LD50, TDLo) for various routes, and exposure limits (OEL-STELs, OEL-TWAs, TLV-TWA, PEL-TWA, REL-TWA). 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, a rat oral LD50, was selected as the TEEL-3 basis. A mouse intraperitoneal TDLo was evaluated for the TEEL-2 basis; however, the effects were not adverse, and it was therefore not selected for TEEL development. Instead, the TEEL-2 value was derived according to Table 3.5. The OEL-STEL (Austria, 15-min average) was selected as the TEEL-1.
• PAC-1 = TEEL-1 = OEL-STEL (Austria; 10 mg/m3)
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = Rat oral LD50 (1600 mg/kg)
This review generated PAC-1 and PAC-2 values inconsistent with Rev. 29A, and a consistent PAC-3. The Rev. 29A and current TEEL-3 values, source, and methodology remain consistent. The Rev. 29A TEEL-2 basis was a mouse intraperitoneal TDLo found in this review, while the current TEEL-2 was derived from the TEEL-3 (Table 3.5). The Rev. 29A TEEL-1 basis was the TLV-TWA, while the current value is a higher priority exposure limit, an OEL-STEL.