A review of available sources identified acute toxicity data (LD50, LC50, LDLo) for various species and routes, and an OEL-TWA (Latvia). 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 most preferred exposure type, a rat LC50 (1.81 mg/L/4H (for both sexes)), was selected as the TEEL-3 basis and was scaled to a 60-minute equivalent using the ten Berge equation (Section 3.3.4). The OEL-TWA (Latvia) was selected as the TEEL-1 basis. The TEEL-2 was derived according to Table 3.5.
• TEEL-1 = OEL-TWA (Latvia, 0.2 mg/m3) x 3
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat LC50 (1.81 mg/L/4H)
This review generated TEEL values inconsistent with Rev. 29A. In Rev. 29A the TEEL-3 basis was a rat oral LD50, however this review found and used a higher priority rat LC50. The TEEL-2 basis remains consistent, with the difference in the value due to the change in the TEEL-3 basis. The Rev. 29A TEEL-1 was derived according to Table 3.5 from the rat oral LD50 toxicity data, while the current basis is an OEL-TWA (Latvia).