A review of available sources identified the following: TWAs (PEL, REL, TLV), an IDLH, and human toxicity data for Cr(III) compounds CASRN: 7440-47-3. Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were selected based on the 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 IDLH (1990), an “effective value”, was selected as the TEEL-3 basis and a molecular weight adjustment applied (Section 3.4.3.2). The human (female) TDLo was selected as the TEEL-2 basis. The PEL-TWA was selected as the TEEL-1 basis and a compound adjustment factor applied (Section 3.2.2).
• TEEL-1 = MW-adjusted PEL-TWA (Cr(III) compounds as Cr, CASRN: 7440-47-3, 0.5 mg/m3) x 3
• TEEL-2 = Human (female) oral TDLO (100 mg/kg; toxicity endpoints reported as “gastrointestinal: nausea or vomiting”).
• TEEL-3 = MW-adjusted IDLH (1990, Cr(III) compounds as Cr, CASRN: 7440-47-3, 250 mg/m3)
This review generated TEEL-3 and TEEL-2 values that are less conservative than those in Rev. 29A. In Rev. 29A, the TEEL-3 and TEEL-2 values were both derived from the PEL-TWA (Table 3.5). Instead, this review selected the IDLH as the TEEL-3 and the PEL-TWA for the TEEL-1, in line with the 1990 IDLH justification (PEL-TWA x 500), as there was “no evidence that an acute exposure to a high concentration of soluble chromic salts would impede escape or cause any irreversible health effects within 30 minutes”. The current TEEL-2 is derived from a human toxicity dose, a more preferred data source (Section 3.6.4).