A review of available sources identified AEGLs and acute toxicity data for this chemical. In addition, there is acute toxicity data available for an isomer (1,2,3-trimethylbenzene, CASRN: 526-73-8). 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. Acute toxicity data for 1,2,4-trimethylbenzene resulted in TEEL-3 values < AEGL-2. Instead, analysts selected the rat oral LDLo for 1,2,3-trimethylbenzene (Section 3.4.6). The dose is reported in units of mL/kg; therefore, the reported density of 1,2,3-trimethylbenzene (0.894 g/m3 at 25°C) was used to convert the dose to mg/kg. The AEGLs were selected as the TEEL-2 and TEEL-1 due to their priority among the emergency exposure limits (Section 1).
• TEEL-1 = AEGL-1
• TEEL-2 = AEGL-2
• TEEL-3 = Rat oral LDLo (1,2,3-trimethylbenzene, CASRN: 526-73-8; 10 mL/kg converted to 8940 mg/kg with density = 0.894 g/m3)
This review generated TEEL-2 and TEEL-1 values consistent with Rev. 29A. The Rev. 29A and current TEEL-3 values reported in mg/m3 are consistent; differences in the values reported in ppm may be due to rounding.