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May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 504-29-0

NIOSH REL: 0.5 ppm (2 mg/m3) TWA

Current OSHA PEL: 0.5 ppm (2 mg/m3) TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.5 ppm (1.9 mg/m3) TWA

Description of substanceL: White powder, leaflets, or crystals with a characteristic odor.

LEL: Unknown

Original (SCP) IDLH: 5 ppm

Basis for original (SCP) IDLH: Very little quantitative data are available on which to base an IDLH for 2-aminopyridine. The chosen IDLH is based on the statement by ACGIH [1971] that a 5-hour exposure to about 5 ppm produced headache, increased blood pressure, and nausea in a worker [Watrous and Schulz 1950].

Short-term exposure guidelines: None developed


Lethal dose data:
SpeciesReferenceRoute(mg/kg)(mg/kg)Adjusted LDValue
RatMarhold 1986oral200-----385 ppm39 ppm
MouseVerschueren 1983oral50-----90 ppm9 ppm

Human data: A 5-hour exposure to approximately 5 ppm caused severe headache, increased blood pressure, flushing of the extremities, and nausea [Watrous and Schulz 1950]

Revised IDLH: 5 ppm [Unchanged]

Basis for revised IDLH: Based on acute inhalation toxicity data in humans [Watrous and Schulz 1950], the original IDLH for 2-aminopyridine (5 ppm) is not being revised at this time. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 5 ppm.


  1. ACGIH [1971]. 2-Aminopyridine. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 11.
  2. Marhold J [1986]. Prehled Prumyslove Toxikologie, Organicke Latky. Prague, Czechoslovakia: Avicenum, p. 838 (in Czechoslovakian).
  3. Verschueren K [1983]. Handbook of environmental data of organic chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold, Co., p. 192.
  4. Watrous RM, Schulz HN [1950]. Cyclohexylamine, p-chlornitrobenzene, 2-aminopyridine: toxic effects in industrial use. Ind Med Surg 19(7):317-320.
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