A review of available sources did not identify exposure limits or acute toxicity data for diisooctyl acid phosphate. Analysts evaluated acute toxicity data (LD50) for a similar chemical bis(2-ethylhexyl) phosphate (CASRN: 298-07-7) 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 lowest reported dose for the most preferred species and route, a rat oral LD50 (1400 mg/kg) for bis(2-ethylhexyl) phosphate was selected as the TEEL-3 basis. TEEL-2 and TEEL-1 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 oral LD50 (bis(2-ethylhexyl) phosphate, CASRN: 298-07-7; 1400 mg/kg)
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was an HHR=2, while the current TEEL-3 basis is a rat oral LD50 for a similar chemical, bis(2-ethylhexyl) phosphate (Section 3.4.6, CASRN: 298-07-7). The Rev. 29A and current TEEL-2 and TEEL-1 use the same methodologies, with differences due to the change in TEEL-3.