A review of available sources did not identify exposure limits or acute toxicity data for cupric nitrite. Instead, analysts evaluated exposure limits (TWAs, STELs) for copper and inorganic compounds (CASRN: 7440-50-8) and acute toxicity data (LD50) for copper nitrate (CASRN: 3251-23-8), since nitrites metabolize to nitrates, 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 species and route data, rat oral LD50 (copper nitrate, CASRN: 3251-23-8), was selected as the TEEL-3 basis. The TEEL-2 was derived according to Table 3.5. The OEL-STEL (Switzerland, inhalable fraction, 15-minute) for copper and inorganic compounds was selected as the TEEL-1 basis and weight adjusted (Section 3.2.2).
• PAC-1 = TEEL-1 = MW-adjusted OEL-STEL (0.2 mg/m3; copper and inorganic compounds, Cu, CASRN: 7440-50-8)
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = Rat oral LD50 (794 mg/kg; copper nitrate, CASRN: 3251-23-8)
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A TEEL-1 basis was the MW-adjusted TLV-TWA for copper, dusts & mists (as Cu, CASRN: 7440-50-8), from which the TEEL-2 and TEEL-3 were derived (Table 3.5). The current TEEL-3 basis is a rat oral LD50 for copper nitrate (CASRN: 3251-23-8), from which the TEEL-2 was derived (Table 3.5). The current TEEL-1 is a MW-adjusted OEL-STEL for copper and inorganic compounds (as Cu, Section 3.2.2).