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Pyridine																				Related Pages
										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 ppmRat
    Smyth et al. 1951
    LC83: 4,000
    -----
    4 hr
    8,000 ppm (2.0)
    800 ppmRat
    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 ppmMouse
    Leslie et al. 1973
    oral
    1,500
    -----
    3,191 ppm
    319 ppmRat
    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 Unpublished paper presented to the American Industrial Hygiene Association Conference, Los Angeles, CA.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.

			
							
								Page last reviewed:  December 4, 2014						Content
							source: 	National Institute for Occupational Safety and Health NIOSH Publications & Products
Immediately Dangerous To Life or Health (IDLH) Values
Table of IDLH Values
Criteria for Determining IDLH Values
Historical Documentation
Original (SCP) Values
Abbreviations for IDLH Documentation
Abbreviations for Journal Titles Follow NIOSH Facebook
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