A review of available sources identified acute toxicity data (LC50, LD50) for several species and routes. In addition, analysts evaluated exposure limits (TLV-TWA, TLV-STEL) for organic tin compounds (no CASRN specified). Data sources were selected according to the hierarchy listed in Table 3.1. Toxicity data were evaluated 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). The TVL-STEL was selected as the TEEL-1 basis and a compound adjustment factor was applied (Section 3.2.2). The TEEL-2 value was derived according to Table 3.5. Analysts evaluated 2-hour rat and mouse LC50 data, with both doses reported as 150 mg/m3 (PAC-3 = TEEL-3 = 5.1 mg/m3), but these resulted in a TEEL-2 < TEEL-1. Instead, rat and mouse oral LD50 studies were evaluated; of these the two rat LD50 studies, 175 mg/kg (1960) and 2071 mg/kg (1981), yielded significantly different TEEL-3 values, therefore the most recent oral study, a mouse oral LD50 (1995) was evaluated. The mouse oral LD50 yielded a TEEL-3 value comparable in magnitude to the 1960 rat oral LD50 (23 mg/m3 v. 35 mg/m3 respectively). The mouse oral LD50 was selected as the TEEL-3 basis because it was 1) the most recent oral study, and 2) it resulted in a conservative TEEL-3 value comparable to other toxicity data (rat oral LD50).
• PAC-1 = TEEL-1 = MW-adjusted TLV-STEL (tin, organic compounds, 0.2 mg/m3)
• PAC-2 = TEEL-2 = TEEL-3/6
• TEEL-3 = Mouse oral LD50 (210 mg/kg)
This review generated PAC-2 and PAC-3 values inconsistent with Rev. 29A and a PAC-1 consistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a rat oral LD50 not found in this review. Although other rat oral LD50 data were found, the yielded values were significantly different in magnitude from each other. Analysts selected a more current mouse oral LD50 (Section 3.3.1) that was comparable in magnitude to both the Rev. 29A TEEL-3 and a rat oral LD50 (1960). The Rev. 29A and current TEEL-2 use the same methodology, with differences due to the change in TEEL-3. The Rev. 29A and current TEEL-1 values, source, and methodology are consistent.