A review of available sources identified no exposure limits or acute toxicity data for manganese oxalate. Reported GHS health hazard codes (H302 and H304, Category 4) for manganese oxalate correspond to an approximate an HHR=3 (PAC-3 = TEEL-3 = 790 mg/m3). Data sources were selected according to the hierarchy listed in Table 3.1. In addition, analysts evaluated exposure limits of manganese compounds (CASRN: 7439-96-5, IDLH, ceiling limits, STELs, TWAs) for TEEL development. The 1990 and 1994 IDLH were compared; the 1990 IDLH was derived from the PEL-TWA, while the 1994 IDLH includes animal inhalation acute toxicity data. Considering this, and the estimated TEEL-3 range from reported GHS health hazards, analysts selected the 1994 IDLH as the TEEL-3 basis. The PEL-C was selected as the TEEL-2. The PEL-STEL was selected as the TEEL-1. A compound adjustment factor was applied to 1994 IDLH, PEL-C, and PEL-STEL (Section 3.2.2).
• 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 = MW-adjusted IDLH (1994, manganese, CASRN: 7439-96-5; 500 mg/m3)
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 was derived from the TEEL-2. The current TEEL-3 basis is a weight adjusted 1994 manganese IDLH, due to its inclusion of inhalation acute toxicity data. The 1994 IDLH was used according to handbook guidelines (Section 4.2-4.3).