A review of available sources identified rat and mouse acute toxicity data (LD50, LC50) for various routes, and exposure limits (OEL-TWA). 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. Although there was a preferred inhalation toxicity data, a mouse LC50, the duration was not reported; therefore, it was not selected for TEEL development. Instead, the next most preferred species and route data, a rat oral LD50, was selected as the TEEL-3 basis. The TEEL-2 value was derived according to Table 3.5. The OEL-TWA (Finland, as Cu) was selected as the TEEL-1 basis and weight adjusted (Section 3.2.2)
• PAC-1 = TEEL-1 = MW-adjusted OEL-TWA (as Cu, 0.02 mg/m3)
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = Rat oral LD50 (140 mg/kg)
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A TEEL-1 basis was a weighted adjusted TLV-TWA for copper, from which the TEEL-2 and TEEL-3 were derived (Table 3.5). The current TEEL-3 basis is a rat oral LD50, from which the TEEL-2 was derived (Table 3.5). The current TEEL-1 basis is an OEL-TWA for cuprous chloride (as Cu) that was weight adjusted (Section 3.2.2, Section 3.4.2)