PAC Database - Detailed Chemical Data

Chemical Identity
Chemical CAS# UN# Health Code Numbers
Ethyl methylphosphonic acid; (EMPA; VX acid; Ethyl methyl phosphonate; Ethyl methyl phosphonic acid) 1832-53-7
14.01
15.02
Formula Synonyms
C3.H9.O3.P
Physical Properties
Mol Wt State MP (°C) BP (°C) VP (Hg) VP (°C) SG LEL (ppm)
124.07606 L 1.172
PAC Values
PAC Values (Original Units: mg/m3)
PAC-1 PAC-2 PAC-3
12 130 790
Converted PAC Values (ppm)
PAC-1 PAC-2 PAC-3
2.4 26 160
Technical Basis
A review of available sources did not identify exposure limits or acute toxicity data for ethyl methylphosphonic acid. Reported GHS health hazard ratings (H315 and H319, Category 2; H335, inhalation Category 3; H301, oral Category 3) indicate a mid-level health hazard, approximately equivalent to an HHR=2. Analysts assumed an HHR=2 as the TEEL-3 basis (Section 3.4.5). TEEL-2 and TEEL-1 values were derived according to Table 3.5.
• PAC-1 = TEEL-1 = TEEL-2/11
• PAC-2 = TEEL-2 = TEEL-3/6
• PAC-3 = TEEL-3 = HHR=2
This review generated PAC values inconsistent with Rev. 29A. The Rev. 29A TEEL-3 basis was a rat oral LD50 for dimethyl methylphosphonate (Section 3.4.6, CASRN: 756-79-6). The current TEEL-3 basis is an assumed HHR=2, from analysis of GHS health hazard statements (Section 3.4.5). The Rev. 29A and current TEEL-2 and TEEL-1 use the same methodology with differences due to the change in TEEL-3.
References
Chemical information and GHS health hazards retrieved from: https://pubchem.ncbi.nlm.nih.gov/compound/449085
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PAC values marked with a subscript "A" correspond to 60-minute AEGL values.
PAC values marked with a subscript "E" correspond to ERPG values.
PAC values marked by * are >= 10% lower explosive limit (LEL) but < 50% LEL.
PAC values marked by ** are > 50% LEL but < 100% LEL.
PAC values marked by *** are >= LEL.