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Diazomethane
May 1994
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 [1963] 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 [1971] 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. |
REFERENCES:
1. ACGIH [1971]. 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 [1931]. Schädliche gase dämpfe, nebel, rauch- und staubarten. Berlin, Germany: Verlag von Julius Springer, p. 420 (in German).
3. Marhold J [1986]. Prehled Prumyslove Toxikologie, Organicke Latky. Prague, Czechoslovakia: Avicenum, p. 496 (in Czechoslovakian).
4. Patty FA, ed. [1963]. 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 [1949]. The mechanism of action of phosgene and diphosgene. Arch Biochem 24:329-337.