There are no exposure limits available for this chemical. A review of sources identified the following exposure data: TLV-TWA and IDLH for Cr(III) compounds and chromates (CASRN: 7440-47-3). A compound adjustment factor was applied to both values according to guidance in the TEEL handbook (Section 3.2.2). A TEEL-2 was calculated from the TEEL-3 value, according to Table 3.5.
• TEEL-1 = MW-adjusted TLV-TWA x 3 for Cr (III) Compounds, as Cr (CASRN: 7440-47-3, 0.003 mg/m3)
• TEEL-2 = TEEL-3/6
• TEEL-3 = MW-adjusted IDLH (1990) for Cr (III) compounds, as Cr (CASRN: 7440-47-3, 250 mg/m3)
This review generated TEEL values significantly less conservative than those in Rev. 29A due to a change in basis. In Rev. 29A, the TEEL-3 basis was a CAF adjusted IDLH for chromic acid and chromates (CASRN: 1333–82–0). During this review, it was observed that this IDLH applies only compounds with Cr (VI). Therefore, the current review developed a TEEL-3 from an IDLH for Cr (III), resulting in less conservative values. This is consistent with the known toxicity of Cr (VI) compounds exceeding that of Cr(III) compounds. The basis of Rev. 29A and the current TEEL-1 are both TLV-TWA, however this review updates the basis to the most current value (2017).