A review of available sources did not identify exposure limits or acute toxicity data for manganese nitrite. Analysts evaluated exposure limits of manganese compounds (CASRN: 7439-96-5, IDLH, ceiling limits, STELs, TWAs) for TEEL development and evaluated the TEEL for a similar chemical, manganese(II) nitrate (CASRN: 10377-66-9) to determine an appropriate TEEL magnitude. Data sources were selected according to the hierarchy listed in Table 3.1. The manganese PEL-STEL and PEL-C were selected as the TEEL-1 and TEEL-2, respectively, and a compound adjustment factor was applied (Section 3.2.2). Analysts evaluated the IDLHs (1990, 1994) and the manganese(II) nitrate TEEL-3 (98 mg/m3), determining that neither IDLH is sufficiently conservative. Instead, the TEEL-3 was derived according to Table 3.5.
• PAC-1 = TEEL-1 = MW-adjusted PEL-STEL (manganese, CASRN: 7439-96-5; 3 mg/m3)
• PAC-2 = TEEL-2 = MW-adjusted PEL-C (manganese, CASRN: 7439-96-5; 5 mg/m3)
• PAC-3 = TEEL-3 = TEEL-2 x 6
This review generated PAC-2 and PAC-1 values consistent with Rev. 29A and a PAC-3 value inconsistent. The Rev. 29A and current TEEL-2 and TEEL-1 use the same sources and methodologies. The Rev. 29A TEEL-3 source and methodology are consistent, therefore minor differences in the values may be due to rounding.