Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 334–88–3
NIOSH REL: 0.2 ppm (0.4 mg/m3) TWA
Current OSHA PEL: 0.2 ppm (0.4 mg/m3) TWA
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 0.2 ppm (0.34 mg/m3) TWA
Description of Substance: Yellow gas with a musty odor.
LEL:. . Unknown
Original (SCP) IDLH: 2 ppm
Basis for original (SCP) IDLH: The only available acute inhalation toxicity data concerning diazomethane is the statement by Patty  that a 10-minute exposure to 175 ppm was lethal for cats [Flury and Zernik 1931]. This concentration is obviously too high for an IDLH. ACGIH  reported that the toxicity of diazomethane seems comparable to that of phosgene. Therefore, the chosen IDLH is based on an analogy with phosgene, which has an IDLH of 2 ppm.
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA
Lethal concentration data:
|Species||Reference||LC50(ppm)||LCLo(ppm)||Time||Adjusted 0.5-hrLC (CF)||Derivedvalue|
|Cat||Marhold 1986||175||—–||10 min||121 ppm (0.69)||12 ppm|
Other animal data: It has been suggested that the toxicity of diazomethane is comparable to that of phosgene, possibly because diazomethane is a strong methylating agent [Potts et al. 1949].
Human data: None relevant for use in determining the revised IDLH.
|Revised IDLH: 2 ppm [Unchanged]Basis for revised IDLH: Based on an analogy to phosgene [Potts et al. 1949] which has an IDLH of 2 ppm, the original IDLH for diazomethane of 2 ppm is not being revised at this time.|
1. ACGIH . Diazomethane. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 71-72.
2. Flury F, Zernik F . Schädliche gase dämpfe, nebel, rauch- und staubarten. Berlin, Germany: Verlag von Julius Springer, p. 420 (in German).
3. Marhold J . Prehled Prumyslove Toxikologie, Organicke Latky. Prague, Czechoslovakia: Avicenum, p. 496 (in Czechoslovakian).
4. Patty FA, ed. . Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., pp. 940, 2214.
5. Potts AM, Simon FP, Gerard RW . The mechanism of action of phosgene and diphosgene. Arch Biochem 24:329-337.