A review of available sources identified the following: mouse LD50 (intraperitoneal, oral) and rat LD50 (oral) acute toxicity data. GHS health hazard ratings were evaluated to determine an estimated magnitude for TEEL values. 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. GHS classifies potassium iodate as an inhalation Category 4 (H335) and skin/eye Category 1 and 2/2A (H315, H318, H319) indicating an estimated HHR=2 or HHR=1, respectively. These corresponding to a TEEL-3 range of 79-790 mg/m3 (Section 3.4.5). The most preferred species and route toxicity data, a rat oral LD50, was selected as the TEEL-3. TEEL-2 and TEEL-1 values were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = Rat oral LD50 oral (1200 mg/kg)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a mouse intraperitoneal LD50, while the current TEEL-3 basis is a rat oral LD50, a more preferred route and species (rat > mouse, oral > intraperitoneal, Section 3.3.3). The current TEEL-3 magnitude is within the expected range estimated from GHS health hazard classifications. The Rev. 29A and current TEEL-2/TEEL-1 values were derived using the same methodology (Table 3.5), with differences due to the change in TEEL-3.