A review of available sources identified acute toxicity data (LD50, LD¬¬¬Lo) for several species and routes. There is also a reported rat LC50; however, the toxicity end points were determined inappropriate for TEEL development (Section 3.3.2). In addition, there are available exposure limits for vanadium (V as V₂O₅; CASRN: 1314-62-1, IDLH, PEL-C, REL-C, TWAs) and vanadium pentoxide (CASRN: 1314-62-1; LOC). 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 vanadium IDLH was considered as a TEEL-3, however analysts selected most preferred species and route toxicity data, a rat oral LD50, as the TEEL-3 basis given that this data corresponds to the actual toxicity and corrosivity of vanadium trioxide. The LOC was considered as a TEEL-2; however, this value was not selected because 1) it is derived from the IDLH, which was not selected as a TEEL-3, and 2) it is an order of magnitude greater than other TEEL-2 available bases (ceiling limits, TWAs; Section 3.3.1). Instead, the most preferred vanadium ceiling limit, the PEL-C, was selected as the TEEL-2 and a compound adjustment factor was applied (Section 3.2.2). The TEEL-1 value was derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = MW-adjusted PEL-C (vanadium dust, as V₂O₅, CASRN: 1314-62-1, 0.5 mg/m³)
• TEEL-3 = Rat oral LD50 (566 mg/kg)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 was a molecular weight adjusted vanadium IDLH, while the current basis is a rat oral LD50 for vanadium trioxide. The Rev.29A TEEL-2 was a molecular weight adjusted REL-C, while the current TEEL-2 is a molecular weight adjusted PEL-C, a more preferred source (Table 3.1). The Rev. 29A and current TEEL-1 values were derived using the same methodology (Table 3.5), with differences due to the change in TEEL-2.