Immediately Dangerous to Life or Health Concentrations (IDLH)
CAS number: 94–75–7
NIOSH REL: 10 mg/m3 TWA
Current OSHA PEL: 10 mg/m3 TWA
1989 OSHA PEL: Same as current PEL
1993-1994 ACGIH TLV: 10 mg/m3 TWA
Description of Substance: White to yellow, crystalline, odorless powder.
LEL:. Noncombustible Solid
Original (SCP) IDLH: 500 mg/m3
Basis for original (SCP) IDLH: The chosen IDLH has been estimated from oral data, because no useful data on acute inhalation toxicity are available. NIOSH  cited a dog oral LD50 of 100 mg/kg [Seabury 1963]. Dudley and Thapar  estimated that the LD50 for humans was between 80 and 800 mg/kg.
Short-term exposure guidelines: None developed
ACUTE TOXICITY DATA
Lethal dose data:
|Species||Reference||Route||LD50(mg/kg)||LDLo(mg/kg)||Adjusted LD||Derived value|
|Cabral et al. 1979Seabury 1963
Senczuk and Pogorzelska 1980
|3,500 mg/m3700 mg/m3
|350 mg/m370 mg/m3
Human data: It has been reported that the lethal oral dose ranges from 80 to 800 mg/kg [Dalgaard-Mikkelsen and Poulsen 1962; Dudley and Thapar 1972]. [Note: Oral doses of 80 to 800 mg/kg are equivalent to a worker being exposed to about 3,700 to 37,000 mg/m3 for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]
|Revised IDLH: 100 mg/m3Basis for revised IDLH: No inhalation toxicity data are available on which to base an IDLH for 2,4-D. Therefore, the revised IDLH for 2,4-D is 100 mg/m3 based on acute oral toxicity data in humans [Dalgaard-Mikkelsen and Poulsen 1962; Dudley and Thapar 1972] and animals [Seabury 1963]. This may be a conservative value due to the lack of relevant acute inhalation toxicity data for workers.|
1. Cabral JRP, Raitano F, Mollner T, Bronczyk S, Shubik P . Acute toxicity of pesticides in hamsters. Toxicol Appl Pharmacol 48:A192 [Abstract].
2. Dalgaard-Mikkelsen SV, Poulsen E . Toxicology of herbicides. Pharmacol Rev 14:225-250.
3. Dudley AW Jr, Thapar NT . Fatal human ingestion of 2,4-D, a common herbicide. Arch Pathol 94:270-275.
4. NIOSH . AG68250. Acetic acid, (2,4-dichlorophenoxy)-. In: Registry of toxic effects of chemical substances, 1976 ed. Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 76-191, p. 21.
5. Seabury JH . Toxicity of 2,4-dichlorophenoxyacetic acid for man and dog. Arch Environ Health 7:202-209.
6. Senczuk W, Pogorzelska H . Budowa chemiczna a toksykodynamiczne wlasciwosci pochodnych kwasow fenoksykarboksylowych. Roczniki Panstwowego Zakladu Higieny 31:373-377 (in Polish).
7. Sine C, ed. . 2,4-D. In: Farm chemicals handbook ’93, p. C102.
- Page last reviewed: December 4, 2014
- Page last updated: December 4, 2014
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