A review of available sources did not identify acute toxicity data or exposure limits for 2,2-dichloropropane. Instead, the acute toxicity data (LD50, LCLo) for a chemical isomer, 1,1-dichloropropane (CASRN: 78-99-9) were evaluated for TEEL development (Section 3.4.6). 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 exposure data, a 4-hour rat LCLo, was selected as the TEEL-3 basis and was scaled to a 60-minute equivalent using the ten Berge equation (Section 3.3.4). TEEL-1 and TEEL-2 values were derived according to Table 3.5.
• PAC-1 = TEEL-1 = TEEL-2/11
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = Rat LCLo (4000 ppm/4H; 1,1-dichloropropane; CASRN: 78-99-9)
This review generated PAC values consistent with Rev. 29A; however, the Rev. 29A and current TEEL-3 sources are inconsistent. The Rev. 29A TEEL-3 basis was a 6-hour rat LCLo, that was not identified during this review; instead, the current TEEL-3 basis is a 4-hour rat LCLo. The Rev. 29A and current TEEL-2 and TEEL-1 use the same methodologies (Table 3.5).