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Extension Toxicology Network

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Michigan State University, Oregon State University, and University of California at Davis. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.


Publication Date: 9/93


Some trade names include Aljaden, Alloxol S, BAS 9052, Checkmate, Expand, Fervinal, Grasidim, Nabu, NP-55, Poast, Tritex-Extra and Vantage.


Products containing sethoxydim must bear the signal word "Caution" on the label (1).


Sethoxydim is a selective postemergence herbicide used to control annual and perennial grass weeds in broad-leaved vegetable, fruit, field and ornamental crops. It also has indoor uses. It is available in emulsifiable concentrate formulations (1).



Sethoxydim is moderately toxic by ingestion (2), and not toxic by dermal absorption (4). It causes skin and eye irritation. Inhalation of dusts or vapors can cause irritation of the throat and nose (2). Other symptoms of poisoning include incoordination, sedation, tears, salivation, tremors, blood in the urine and diarrhea (4). Sethoxydim does not cause allergic skin reactions (4).

The oral LD50 for sethoxydim in rats is 3,200 to 3,500 mg/kg. The dermal LD50 in rats is > 5,000 mg/kg (1). The 4-hour inhalation LC50 for sethoxydim in rats is > 6.28 mg/l (1).


Long-term contact with sethoxydim can cause redness and swelling of the eyes or skin (2). No adverse effects were observed in mice given 0, 2, 6, or 18 mg/kg/day for 2 years (6). In another 2-year study with mice fed doses as high as 162 mg/kg/day, the NOEL for non-carcinogenic effects was 18 mg/kg/day (6). The NOEL in a 1-year dog feeding study was 8.86 mg/kg/day for males and 9.41 mg/kg/day for females. The highest dose tested was 110 mg/kg/day for males and 129 mg/kg/day for females. Doses above the NOEL produced equivocal evidence for the occurrence of anemia (6).

Reproductive Effects

When pregnant rabbits were fed 0, 40, 160 or 480 mg/kg/day, there were decreased litter size, low fetal weights, severe maternal weight loss, increased fetal resorptions, spontaneous abortions, and maternal deaths at the 480 mg/kg level. The NOEL for this study was 160 mg/kg/day (6).

Teratogenic Effects

No developmental effects were observed at any dose level when pregnant rats were fed 0, 40, 100 or 250 mg/kg/day (6).

Mutagenic Effects

Several tests for mutagenicity of sethoxydim have produced negative results (6).

Carcinogenic Effects

No carcinogenic effects were observed at any dose level when mice were fed 0, 6, 18, 54 or 162 mg/kg/day for 2 years (6).

Organ Toxicity

No information was found.

Fate in Humans and Animals

No information was found.


Effects on Birds

Sethoxydim is of low toxicity to birds. The acute oral LD50 for sethoxydim in mallard ducks is > 2,510 mg/kg. Its dietary LD50 in mallards and bobwhite quail is > 5,620 ppm (8).

Effects on Aquatic Organisms

Sethoxydim is moderately toxic to trout and weakly toxic to carp (1). The LC50 for sethoxydim in bluegill sunfish is 265 mg/l and 170 mg/l in rainbow trout (8). Its LC50 in Daphnia magna, a small freshwater crustacean, is 78.1 ppm (8).

Effects on Other Animals (Nontarget species)

Sethoxydim has low toxicity to wildlife (4). It is non-toxic to bees (1).


Some degradation occurswith UV and sunlight (4).

Breakdown of Chemical in Soil and Groundwater

Sethoxydim has a weak tendency to adsorb to soil particles (4). Laboratory soil leaching tests have suggested that sethoxydim could leach in soil. However, in field tests, sethoxydim did not leach below the top 4 inches of soil and it did not persist (8).

On soil, photodegradation of sethoxydim takes less than 4 hours (4). The product Poast will photodegrade on oil surfaces with a half-life of approximately 3.7 hours (8). Disappearance of sethoxydim is primarily due to action by soil microbes. Its half-life on a loamy sand at pH 6.8 was 4 to 5 days, and on a loam soil at pH 7.4 was 11 days (4, 8).

Breakdown of Chemical in Surface Water

In water, photodegradation of sethoxydim takes less than 1 hour (4). The product Poast is fairly stable to hydrolysis, with a half-life of about 40 days at pH 7 and 25!C (8).

Breakdown of Chemical in Vegetation

Sethoxydim is absorbed rapidly by foliage and moves both upward and downward in plants from the point of absorption. Sethoxydim was rapidly metabolized in soybeans (4). The product Poast does accumulate in the tissues of crops planted in fields after harvest of treated crops. Measured residues were all below 0.066 ppm (8).


Sethoxydim is an yellowish-brown, oily liquid (1). Formulated products containing sethoxydim are stable at normal temperatures and pressures, but unformulated sethoxydim decomposes at room temperature (4). Thermal decomposition of sethoxydim may release toxic or hazardous gases (2).

Workers handling sethoxydim should avoid contact of this material with eyes, skin or clothing (2).

Exposure Guidelines:

No occupational exposure limits have been established for sethoxydim by OSHA, NIOSH or ACGIH (2).

ADI: 0.09 mg/kg/day based on a NOEL of 8.86 in a 1-year dog feeding study and a 100 fold safety margin (6).

Physical Properties:

CAS #: 74051-80-2
Chemical name: 2[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one
Chemical Class/Use: cyclohexanone herbicide
Specific gravity: 1.043 at 25 degrees C (technical) (4)
H20 solubility: 4700 ppm at pH 7; 25 ppm at pH 4 (1)
Solubility in other solvents: readily soluble in most organic solvents; freely soluble in methanol, hexane and xylene (1)
Melting point: > 194 degrees F (> 90 degrees C) (2)
Boiling point: > 90 degrees C at 3 x 10-5 mm Hg (5)
Decomposition temperature: unstable at room temperature if not formulated (4)
Vapor pressure: 1.6 x 10-7 mm Hg at 25 degrees C (3, 4)
Koc: 50 (7)


BASF Corp.
Agricultural Products Group
PO Box 13528
2505 Meridian Pkwy.
Research Triangle Park, NC 27709-3528

Review by Basic Manufacturer:

Comments solicited: April, 1993
Comments received:


  1. Meister, R.T. (ed.). 1992. Farm Chemicals Handbook '92. Meister Publishing Company, Willoughby, OH.
  2. Occupational Health Services, Inc. 1992 (Nov. 17). MSDS for Sethoxydim. OHS Inc., Secaucus, NJ.
  3. U. S. Department of Agriculture, Soil Conservation Service. 1990 (Nov.). SCS/ARS/CES Pesticide Properties Database: Version 2.0 (Summary). USDA - Soil Conservation Service, Syracuse, NY.
  4. WSSA Herbicide Handbook Committee. 1989. Herbicide Handbook of the Weed Science Society of America, 6th Ed. WSSA, Champaign, IL.
  5. British Crop Protection Council. 1983. The Pesticide Manual: A World Compendium, 7th ed. Croydon, England.
  6. U.S. Environmental Protection Agency. March 20, 1991. Pesticide tolerances for 2[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy- 2-cyclohexen-1-one. Federal Register 56 (54): 11677-8.
  7. US Environmental Protection Agency. May 8, 1992. Pesticide Environmental Fate One Line Summary: Sethoxydim. Environmental Fate and Effects Division, US EPA, Washington, DC.
  8. US Environmental Protection Agency. June 23, 1989. EEB Chemical Profile: Sethoxydim. US EPA, Washington, DC.