A review of available sources did not identify exposure limits or acute toxicity data for cesium nitrite. Analysts evaluated and acute toxicity data (LD50) for a similar chemical, cesium nitrate (CASRN: 7789-18-6) 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 source and route toxicity data for cesium nitrate, a rat oral LD50, was selected as the TEEL-3 basis (Section 3.4.6). 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 (cesium nitrate, CASRN: 7789-18-6, 2390 mg/kg)
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A TEEL-1 basis was a TLV-TWA for particles not otherwise specified (Section 3.5.2), from which the TEEL-2 and TEEL-3 were derived (Table 3.5). The current TEEL-3 basis is rat oral LD50 for cesium nitrate (Section 3.4.6, CASRN: 7789-18-6), from which TEEL-2 and TEEL-1 values were derived (Table 3.5).