PAC Database - Detailed Chemical Data

Chemical Identity
Chemical CAS# UN# Health Code Numbers
Isocyanic acid 75-13-8
11.01
14.01
14.02
Formula Synonyms
CHNO
Physical Properties
Mol Wt State MP (°C) BP (°C) VP (Hg) VP (°C) SG LEL (ppm)
43.02 G unstabl 996 25
PAC Values
PAC Values (Original Units: ppm)
PAC-1 PAC-2 PAC-3
2.0 7.1 15
Converted PAC Values (mg/m3)
PAC-1 PAC-2 PAC-3
3.5 12 26
Technical Basis
Isocyanic acid is a conjugate acid of cyanate and a chemical compound of cyanide. A review of available sources did not identify acute toxicity data or exposure limits for isocyanic acid. Instead, a review of available sources identified AEGLs for a similar chemical, hydrogen cyanide (CASRN: 74-90-8). The AEGLs were selected as the TEELs due to their priority among the emergency exposure limits (Section 1).
• TEEL-1 = AEGL-1 (hydrogen cyanide, CASRN: 74-90-8)
• TEEL-2 = AEGL-2 (hydrogen cyanide, CASRN: 74-90-8)
• TEEL-3 = AEGL-3 (hydrogen cyanide, CASRN: 74-90-8)
This review generated TEEL values consistent with Rev. 29A*.
References
Chemical information: https://pubchem.ncbi.nlm.nih.gov/compound/Isocyanic-acid
AEGLs (hydrogen cyanide, CASRN: 74-90-8) (Table 5-1) retrieved from: https://www.epa.gov/aegl/hydrogen-cyanide-results-aegl-program
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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.