Skip directly to local search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home
May 1994

Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs)


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:
  LL50 LCLo   Derived
Species Reference Route (mg/kg) (mg/kg) Adjusted LD Value
Rat Marhold 1986 oral 200 ----- 385 ppm 39 ppm
Mouse Verschueren 1983 oral 50 ----- 90 ppm 9 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.
Contact Us: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO