---

The information in this profile may be out-of-date. It was last revised in 1996. EXTOXNET no longer updates this information, but it may be useful as a reference or resource.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.

---

E X T O X N E T

Extension Toxicology Network

Pesticide Information Profiles

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

EXTOXNET primary files maintained and archived at Oregon State University

Revised June 1996

Butylate

Trade and Other Names: Trade names include Anelirox, Anelda Plus, Aneldazin, Butilate, Carbamic Acid, Ethyl N, Genate, Genate Plus, N-Diisobutylthiocarbamate, R1910, Stauffer R-1, Sutan, and Sutan 6E.

Regulatory Status: Butylate is classified by the U.S. Environmental Protection Agency as a General Use Pesticide (GUP), with applications limited to corn fields. It is categorized toxicity class III - slightly toxic. Products containing butylate bear the Signal Word CAUTION.

Chemical Class: thiocarbamate

Introduction: Butylate is an herbicide and a member of the thiocarbamate class of chemicals. It is registered only for use in corn to control grassy weeds such as nutgrass and millet grass, as well as some broadleaf weeds. It is applied to soil immediately before corn is planted, often in combination with atrazine and/or cyanazine. Butylate acts selectively on seeds of weeds that are in the germination stage of development. It is absorbed from the soil by shoots of grass seedlings before they emerge, causing shoot growth to be slowed, and leaves to become twisted.

Formulation: Not Available

Toxicological Effects:

• Acute toxicity: The major routes of exposure to butylate are through the skin and by inhalation. Butylate is a thiocarbamate, a class of chemicals known for their tendency to irritate the skin and the mucous membranes of the respiratory tract. It may cause symptoms of scratchy throat, sneezing, and coughing when large amounts of dusts or spray are inhaled (4,7). Slight eye irritation can be caused by butylate, potentially leading to permanent eye damage [7,22]. Skin irritation was observed in rabbits topically exposed to 2000 mg of technical butylate (85.71% pure) for 24 hours. The acute dermal LD50 for butylate is greater than 4640 mg/kg in rabbits [7]. Butylate causes irritation to the eyes of rabbits [23]. The oral LD50 for butylate ranges from 1659 mg/kg in male guinea pigs to 5431 mg/kg in female rats. Butylate's inhalation LC50 (2-hour) is 19 mg/L [3,23].
• Chronic toxicity: Application of 21 doses of 20 and 40 mg/kg/day to the skin of rabbits caused no effects other than local skin irritation [23]. Liver changes were produced by doses of 180 mg/kg/day in a 56-week rat study with butylate. Blood clotting was affected by 10 mg/kg/day in the same experiment [24]. Several studies have shown that long-term exposure to high doses of butylate causes increases in liver weights in test animals [23]. When butylate was fed to rats at doses of 50, 100, 200, or 400 mg/kg/day for 2 years, body weights were decreased and liver-to-body weight ratios increased at all but the lowest dose tested. In rats fed 20, 80 or 120 mg/kg/day for 2 years, no effects were observed at the 20 mg/kg dose, but kidney and liver lesions formed at the two higher doses. Butylate fed to rats at 10, 30 and 90 mg/kg/day for 56 weeks affected blood clotting at all doses. At the two higher doses body weight and testes:body weight ratios decreased, liver:body weight ratios increased, and lesions formed on the testes. In a study of dogs fed 5, 25, or 100 mg/kg/day for 12 months, decreased body weights, increased liver weights, and increased incidence of liver lesions were observed at the highest dose [23].
• Reproductive effects: No reproductive effects were observed in test animals receiving doses of up to 24 mg/kg/day of butylate [24]. Long-term consumption of water containing butylate at very high doses caused damage to testes in rats [4]. Butylate is unlikely to cause reproductive effects in humans at expected exposure levels.
• Teratogenic effects: No teratogenic effects were observed in offspring of mice ingesting 4 to 24 mg/kg/day of Sutan during days 6 through 18 of pregnancy. No teratogenic effects were observed in the offspring of rats given up to 1000 mg/kg/day on days 6 through 20 of pregnancy or in the offspring of rabbits given doses of up to 500 mg/kg/day on days 6 through 18 of gestation [23,24]. However, in a study of two generations of offspring from rats fed for 63 days before mating, decreased brain weights were observed in the first generation of offspring at the 50 mg/kg/day dose. At 200 mg/kg/day, adverse effects on the eyes and kidneys of the first generation were observed. This evidence suggests that butylate is unlikely to cause teratogenic effects in humans under normal circumstances.
• Mutagenic effects: Mutations were seen in mice given very high oral doses of 1000 mg/kg/day of the herbicide [25]. It was not mutagenic in the Ames test, performed on Salmonella bacteria [4,24]. Butylate thus is nonmutagenic or very weakly mutagenic.
• Carcinogenic effects: There was no tumor formation related to doses of up to 320 mg/kg/day of the herbicide in a 24-month study of rats. Thus, butylate does not appear to be carcinogenic [24].
• Organ toxicity: Animal studies have shown the liver and male reproductive system as the target organs.

• Fate in humans and animals: Butylate is rapidly metabolized and excreted in animals [24]. Within 48 hours after administration of butylate to rats by gavage, 27.3 to 31.5% of the material is eliminated through the urine, 60.9 to 64% is expired as carbon dioxide, and 3.3 to 4.7% is excreted in the feces. Only 2.2 to 2.4% of the compound is retained in the body, with most of this located in the blood, kidneys, and liver [23].

Ecological Effects:

• Effects on birds: Given its low toxicity, butylate is considered a minimal hazard to birds [24]. Technical butylate has an acute oral LD50 greater than 4640 mg/kg in mallard ducks. Its 8-day dietary LC50 in bobwhite quail is estimated at 40,000 ppm [22].
• Effects on aquatic organisms: Butylate is moderately toxic to fish [3]. It has a low to moderate potential for bioaccumulation in fish [23]. The LC50 for a 96-hour exposure to technical Sutan ranges from 4.2 mg/L in rainbow trout, to 6.9 mg/L in bluegill sunfish [24].
• Effects on other organisms: Butylate is not harmful to bees if it is used appropriately [3]. It appears to pose few, if any, acute toxicological hazards to non-target wildlife [24].

Environmental Fate:

• Breakdown in soil and groundwater: Butylate has a low to moderate persistence in soil. The soil half-life is 3 to 10 weeks in moist soils under aerobic conditions. Under anaerobic conditions, butylate has a half-life of 13 weeks [23]. In loamy soil, at 70 to 80 F, its half-life is 3 weeks [7]. Soil half-lives of 12 days and 1 1/2 to 3 weeks have also been reported [7,20]. Butylate is one of the pesticide compounds that the EPA considers to have the greatest potential for leaching into groundwater although it is only slightly soluble in water [23]. Butylate does not strongly adsorb to soil particles and is slightly to highly mobile in soils, depending on the soil type [20,23]. Leaching is more likely to occur in sandy, dry soils, and is less likely to occur in soil with higher amounts of organic matter and clay. An EPA study found butylate in 2 out of 152 groundwater samples analyzed [23]. Butylate degrades to sulfoxide in soil [8]. Butylate has a residual activity in soil of approximately 4 months, when it is applied at 5 to 6 mg/hectare [3]. When applied to dry soil surfaces, very little butylate is lost through vaporization. However, it can be lost by vaporization when applied to the surface of wet soils without being sufficiently incorporated [7].
• Breakdown in water: Very low concentrations of butylate ( maximum of 0.0047 mg/L) were found in 91 of 836 surface water samples analyzed [23].
• Breakdown in vegetation: Butylate is readily adsorbed by plant leaves, but does not usually come in contact with foliage. It is rapidly taken up by the roots of corn plants and moved upward throughout the entire plant [7]. Butylate is rapidly broken down in corn roots and leaves, to carbon dioxide, fatty acids, and certain natural plant constituents [7,22]. It is not thought to persist in plants since it disappeared from the stems and leaves of corn plants 7 to 14 days after treatment. The injury that it causes is not limited to that part of the plant to which it is applied [26].

Physical Properties:

• Appearance: Technical butylate is a clear amber to yellow liquid with an aromatic odor [3].
• Chemical Name: S-ethyl-di-isobutylthiocarbamate [3]
• CAS Number: 2008-41-5
• Molecular Weight: 217.38
• Water Solubility: 45 mg/L in water @ 22 C [3]
• Solubility in Other Solvents: kerosene, v.s.; xylene, v.s.; acetone, v.s.; ethyl alcohol, v.s. [3]
• Melting Point: Not Available
• Vapor Pressure: 170 mPa @ 25 C [3]
• Partition Coefficient: 4.1461 [3]
• Adsorption Coefficient: 400 [20]

Exposure Guidelines:

• ADI: Not Available
• MCL: Not Available
• RfD: 0.05 mg/kg/day [27]
• PEL: Not Available
• HA: 0.35 mg/L [4]
• TLV: Not Available

Basic Manufacturer:

Zeneca Ag Products
1800 Concord Pike
Wilmington, DE 19897

• Phone: 800-759-4500
• Emergency: 800-759-2500
  

References:

References for the information in this PIP can be found in Reference List Number 4

DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide product labeling or other regulatory requirements. Please refer to the pesticide product labeling.