Pyridine
May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 110–86–1
NIOSH REL: 5 ppm (15 mg/m3) TWA
Current OSHA PEL: 5 ppm (15 mg/m3) TWA
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 5 ppm (16 mg/m3) TWA
Description of substance: Colorless to yellow liquid with a nauseating, fish-like odor.
LEL: . 1.8% (10% LEL, 1,800 ppm)
Original (SCP) IDLH: 3,600 ppm
Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by Patty [1963] that 2 of 3 rats died following a 6-hour exposure to 3,600 ppm [Fassett and Roudabush 1953].
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA:
Lethal concentration data:
| Species | Reference | LC50 (ppm) |
LCLo (ppm) |
Time | Adjusted 0.5-hr LC (CF) |
Derived value |
| Rat | Fassett & Roudabush 1953 | LC66: 3,600 | ----- | 6 hr | 8,280 ppm (2.3) | 828 ppm |
| Rat | Smyth et al. 1951 | LC83: 4,000 | ----- | 4 hr | 8,000 ppm (2.0) | 800 ppm |
| Rat | Vernot et al. 1977 | 9,000 | ----- | 1 hr | 11,250 ppm (1.25) | 1,125 ppm |
Lethal dose data:
| Species | Reference | Route | LD50 (mg/kg) |
LDLo (mg/kg) |
Adjusted LD | Derived value |
| Rat | Biofax 1970 | oral | 891 | ----- | 1,896 ppm | 190 ppm |
| Mouse | Leslie et al. 1973 | oral | 1,500 | ----- | 3,191 ppm | 319 ppm |
| Rat | Smyth et al. 1951 | oral | 1,580 | ----- | 3,362 ppm | 386 ppm |
Human data: Nausea, headache, insomnia, nervousness, and low back or abdominal discomfort with urinary frequency have occurred in individuals exposed to concentrations averaging 125 ppm for 4 hours/day for 1 to 2 weeks [Patty 1963]. Chronic poisoning with mild symptoms of central nervous system injury occurred in workers at a plant where pyridine vapor concentrations ranged from 6 to 12 ppm [Tessinger 1948].
| Revised IDLH: 1,000 ppm Basis for revised IDLH: The revised IDLH for pyridine is 1,000 ppm based on acute inhalation toxicity data in animals [Vernot et al. 1977]. |
REFERENCES:
1. Biofax [1970]. Data sheet 14. Northbrook, IL: Biofax Industrial Bio-Test Laboratories, Inc.
2. Fassett DW, Roudabush RL [1953]. Toxicity of pyridine derivatives with relationship to chemical structure. Unpublished paper presented to the American Industrial Hygiene Association Conference, Los Angeles, CA.
3. Leslie GB, Hanahoe THP, Ireson JD, Sturman G [1973]. Some pharmacological properties of pyridine. Pharmacol Res Commun 5(4):341-365.
4. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. II. Toxicology. New York, NY: Interscience Publishers, Inc., pp. 2190, 2727-2731.
5. Smyth HF Jr, Carpenter CP, Weil CS [1951]. Range-finding toxicity data: list IV. AMA Arch Ind Hyg Occup Med 4:119-122.
6. Teisinger J [1948]. Mild chronic intoxication with pyridine. Czech Med J 39(1947); abstracted in J Ind Hyg Toxicol 30:58. [From ACGIH [1991]. Pyridine. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 1328-1330.]
7. Vernot EH, MacEwen JD, Haun CC, Kinkead ER [1977]. Acute toxicity and skin corrosion data for some organic and inor ganic compounds and aqueous solutions. Toxicol Appl Pharmacol 42(2):417-423.