2-aminopyrazine is a member of pyrazines. A review of available sources did not identify exposure limits or acute toxicity data for 2-Aminopyrazine. Instead, exposure limits (IDLH, TLV-TWA, PEL-TWA, REL-TWA) and acute toxicity data for various species and routes of a similar chemical, 2-aminopyridine (C5H6N2, CASRN: 504-29-0, Section 3.4.6), were evaluated for TEEL development. 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 source, the IDLH (1990, CASRN: 503-29-0), was selected as the TEEL-3. The TLV-TWA was evaluated as a TEEL-1 basis; however, it resulted in a TEEL-3 > TEEL-2. Instead, TEEL-1 and TEEL-2 values were derived according to Table 3.5.
• TEEL-1 = TEEL-2/11
• TEEL-2 = TEEL-3/6
• TEEL-3 = IDLH (1990, 2-aminopyridine CASRN: 504-29-0, 5 ppm)
This review generated TEEL values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a rat oral LD50 for 2-aminopyridine while the current TEEL-3 is an IDLH for 2-aminopyridine, a more preferred source (Table 3.1). The Rev. 29A and current TEEL-2/TEEL-1 used the same methodology (Table 3.5), with differences due to the change in TEEL-3.