A review of available sources identified exposure limits (OEL-STEL, TWAs) and acute toxicity data (LC50, LD50) for numerous routes and species. AEGLs for cadmium (CASRN: 7440-43-9) were considered to determine expected magnitude of TEELs for cadmium oxide. 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. Inhalation exposures were scaled to 60-minute equivalents using the ten Berge equation (Section 3.3.4). Analysts selected the most preferred route and species toxicity data for cadmium oxide, a monkey LC50, as the TEEL-3 basis. Human data was considered as a TEEL-2 basis (TCLo); however, the toxicity endpoints were not reported. Instead, the TEEL-2 value was derived according to Table 3.5. The OEL-STEL (South Africa) was selected as the TEEL-1.
• TEEL-1 = OEL-STEL (South Africa, 0.05 mg/m3)
• TEEL-2 = TEEL-3/6
• TEEL-3 = Monkey LC50 (1500 mg/m3/10M)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEELs were molecular weight adjusted cadmium AEGLs; per Section 3.2.2, AEGLs may not be weight adjusted. Instead, analysts selected available acute toxicity data for cadmium oxide as the TEEL-3 basis, derived the TEEL-2 value from this TEEL-3, and selected an exposure limit as the TEEL-1 (OEL-STEL).