A review of available sources identified exposure limits (OEL-STEL, OEL-TWA) and limited acute toxicity data (LD50). 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 rat oral LD50 was selected as the TEEL-3 basis. The TEEL-2 value was derived according to Table 3.5. An OEL-STEL (Austria) was selected as the TEEL-1 basis; this exposure limit includes the note that the limit is reported “as copper”; therefore, analysts applied a compound adjustment factor (Section 3.2.2).
• TEEL-1 = MW-adjusted OEL-STEL (Austria; 15-min, 5 mg/m3)
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LD50 (1265 mg/kg)
This review generated TEEL values that are inconsistent with Rev. 29A. The Rev. 29A TEEL values were molecular weight adjusted cyanide TEELs. Copper and cyanide each have associated toxicities; in this review, analysts selected an approach that relies on available data specific to copper chloride. As such, current TEELs were developed by 1) selecting the acute toxicity data (rat oral LD50) for copper cyanide as the TEEL-3 basis, 2) deriving the TEEL-2 from the TEEL-3 (Table 3.5), and 3) selecting an exposure limit (OEL-STEL) for copper chloride as the TEEL-1 basis.