A review of available sources identified exposure limits (IDLH, ceiling limits) and acute toxicity data (LD50). 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 IDLH was selected as the TEEL-3. The TLV-C was selected as the TEEL-2. It is important to note that these exposure limits are for a mixture of terphenyl isomers (o-,m-,p-isomers), without a defined ratio, and may be less conservative that toxicities for individual isomers. The TEEL-1 values were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TLV-C (5 mg/m3)
• TEEL-3 = IDLH (1990, 900 mg/m3)
This review generated TEEL-3 values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a mouse LD50 while the current TEEL-3 is an IDLH, a more preferred source (Table 3.1). The TEEL-2 and TEEL-1 values, source, and methodology are consistent with Rev. 29A.