Technical Basis
A review of available sources did not identify exposure limits and limited acute toxicity data (LD50, LDLo). Reported GHS health hazard codes (H302, H304 and H332, Category 4) for manganese oxalate correspond to an approximate HHR=2 (PAC-3 = TEEL-3 = 790 mg/m3). In addition, analysts evaluated exposure limits of manganese compounds (CASRN: 7439-96-5, IDLH, ceiling limits, STELs, TWAs) for TEEL development. Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were evaluated 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 rat LD50 was reported unclear administration techniques, therefore it was not selected (see ECHA record, Section 3.3.1). The rabbit LCLo was evaluated, but the conservatism of the resultant TEEL-3 was not support by GHS health hazard codes. 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).
References
Chemical information: https://pubchem.ncbi.nlm.nih.gov/compound/Manganese-dioxide
Rat oral LD50. EHP, Environmental Health Perspectives., 10(95), 1975 [PMID:1157799]. https://pubchem.ncbi.nlm.nih.gov/compound/Manganese-dioxide and https://echa.europa.eu/mt/registration-dossier/-/registered-dossier/15404/7/3/2
Rabbit intravenous LDLo (45 mg/kg). Merck Index; an Encyclopedia of Chemicals, Drugs, and Biologicals, 11th ed., Rahway, NJ 07065, Merck & Co., Inc. 1989, 11(899), 1989. Retrieved from: https://pubchem.ncbi.nlm.nih.gov/compound/Manganese-dioxide
Manganese information: https://pubchem.ncbi.nlm.nih.gov/compound/Manganese
Manganese IDLH: https://www.cdc.gov/niosh/idlh/7439965.html
Manganese exposure limits: https://www.osha.gov/chemicaldata/501