A review of available sources did not identify exposure limits or acute toxicity data for cyclotol. Cyclotol is a mixture of RDX (cyclonite, CASRN: 121-82-4) and TNT (CASRN: 118-96-7), with a ratio of either 70/30 or 75/25 percent RDX to TNT. As such, analysts evaluated available exposure limits and acute toxicity for RDX and TNT for TEEL development (Section 3.4.6). 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. Analyst selected the most current, lowest dose rat oral LD50 for RDX as the TEEL-3 basis because 1) RDX is more toxic than TNT, and 2) RDX is the primary component of cyclotol. The TEEL-2 was derived according to Table 3.5. The PEL-TWA for RDX was selected as the TEEL-1 basis.
• PAC-1 = TEEL-1 = PEL-TWA (RDX, CASRN: 121-82-4, 0.07 mg/m3) x 3
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = Rat oral LD50 (RDX, CASRN: 121-82-4, 71 mg/kg)
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A TEEL-1 was the RDX REL-STEL, from which TEEL-2 and TEEL-3 values were derived. In the current review, analysts prioritized TEEL-3 development, selecting a rat oral LD50 as the TEEL-3 basis. The TEEL-2 was derived from this TEEL-3. The current TEEL-1 was derived from a PEL-TWA.