Terbacil

Pesticide -> EPA IRIS

Herbicides

Active substance -> EU Pesticides database: Not approved

Pesticides -> Herbicides, Other

Pesticide (Terbacil) -> USDA PDB

Pesticide

log Kow = 1.89

1.44

White crystalline solid

Colorless crystals

Solubilities (g/kg, 25 °C): dimethylformamide 337 g/kg; cyclohexanone 220; methyl isobutyl ketone 121; butyl acetate 88 g/kg; xylene 65

Sparingly soluble in mineral oils and aliphatic hydrocarbons; readily soluble in strong aqueous alkalis

In water, 710 mg/L at 25 °C

175-177 °C

Stable up to the melting point; stable in aqueous alkaline media at room temperature

0.00000047 [mmHg]

4.7X10-7 mm Hg at 29.5 °C

This chemical does not meet GHS hazard criteria for 1.2% (1 of 84) of reports.

Warning

H302 (65.5%): Harmful if swallowed [Warning Acute toxicity, oral]

P264, P270, P273, P301+P317, P330, P391, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 84 reports by companies from 5 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Warning

Hazard Traits - Developmental Toxicity

2002/2076

Terbacil: Does not have an individual approval but may be used as a component in a product covered by a group standard. It is not approved for use as a chemical in its own right.

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Nonflammable

May be ignited by heat or open flame. /Sinbar Herbicide/

USEPA/Office of Pesticide Programs; Reregistration Eligibility Decision Document - Terbacil, EPA 738-R-97-011 (January 1998). The RED summarizes the risk assessment conclusions and outlines any risk reduction measures necessary for the pesticide to continue to be registered in the U.S.[Available from, as of January 6, 2011: http://www.epa.gov/pesticides/reregistration/status.htm]

Tolerances are established for combined residues of the herbicide terbacil, (3-tert-butyl-5-chloro-6-methyluracil) and its metabolites [3-tert-butyl-5-chloro-6-hydroxymethyluracil], [6-chloro-2,3-dihydro-7-hydroxymethyl 3,3-dimethyl-5H-oxazolo(3,2-a) pyrimidin-5-one], and [6-chloro-2,3-dihydro-3,3,7-trimethyl-5H-oxazolo(3,2-a) pyrimidin-5-one], calculated as terbacil, in or on the following raw agricultural commodities: [Table#3141]

Based on the reviews of the generic data for the active ingredient terbacil, the Agency has sufficient information on the health effects of terbacil and on its 78 potential for causing adverse effects in fish, wildlife, and the environment. The Agency has determined that terbacil products, labeled and used as specified in this Reregistration Eligibility Decision, will not pose unreasonable risks or adverse effects to humans or the environment. Under the Food Quality Protection Act of 1996, the Agency has determined that a reasonable certainty of no harm will result to infants and children or to the general population from aggregate exposure to terbacil. Therefore, the Agency concludes that products containing terbacil for all uses are eligible for reregistration.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their continued use. Under this pesticide reregistration program, EPA examines newer health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether the use of the pesticide does not pose unreasonable risk in accordance to newer saftey standards, such as those described in the Food Quality Protection Act of 1996. Terbacil is found on List A, which contains most pesticides that are used on foods and, hence, have a high potential for human exposure. List A consists of the 194 chemical cases (or 350 individual active ingredients) for which EPA issued registration standards prior to FIFRA '88. Case No: 0039; Pesticide type: herbicide; Registration Standard Date: 09/12/89; Case Status: RED Approved 09/97; OPP has made a decision that some/all uses of the pesticide are eligible for reregistration, as reflected in a Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): Terbacil; Data Call-in (DCI) Date(s): 03/03/95, 10/13/95; AI Status: OPP has completed a Reregistration Eligibility Decision (RED) document for the case/AI.

Acute Tox. 4 (65.5%)

Serious eye damage/eye irritation - Category 2B

Extinguishing Media: Use extinguishing media as appropriate for combustibles involved in fire. /Sinbar Herbicide/

Wear self-contained breathing apparatus, pressure demand, MSHA/NIOSH (approved or equivalent) and full protective gear. /Sinbar Herbicide/

Do not contaminate water, food or feed by storage ... .

Store product in original container only. Store in a cool, dry place. /Sinbar Herbicide/

Store in cool, dry well ventilated areas away from ignition sources, heat or flame. Protect containers from physical damage and contamination. /Sinbar Herbicide/

Safe Storage of Pesticides. Always store pesticides in their original containers, complete with labels that list ingredients, directions for use, and first aid steps in case of accidental poisoning. Never store pesticides in cabinets with or near food, animal feed, or medical supplies. Do not store pesticides in places where flooding is possible or in places where they might spill or leak into wells, drains, ground water, or surface water. /Residential users/

Do not contaminate water when cleaning of equipment or disposing of equipment washwaters or rinsate. /Sinbar Herbicide/

Small Releases: Clear area. Shut off leak if safely possible. Do not wash small spills away. Ensure adequate ventilation. Do not discharge into drains or surface waters/groundwater. Shovel material into a suitable container for disposal. If spill area is on ground near trees or other valuable plants, remove top two inches of soil after initial cleanup. Dispose as directed by pesticide product. /Sinbar Herbicide/

Large Releases: Cordon off area of spillage and dike area with dirt, sand or other inert material to prevent any further migration. Recover as much of usable product for application (best disposal practice). Handle remaining material as a small spill. /Sinbar Herbicide/

If a spill occurs, clean it up promptly. Don't wash it away. Instead, sprinkle the spill with sawdust, vermiculite, or kitty litter. Sweep it into a plastic garbage bag, and dispose of it as directed on the pesticide product label./Residential users/

After Applying a Pesticide, Indoors or Outdoors. To remove pesticide residues, use a bucket to rinse tools or equipment three times, including any containers or utensils that you used when mixing the pesticide. Then pour the rinsewater into the pesticide sprayer and reuse the solution by applying it according to the pesticide product label directions. After applying any pesticide wash your hands and any other parts of your body that may have come in contact with the pesticide..To prevent tracking pesticides inside, remove or rinse your boots or shoes before entering your home. Wash any clothes that have been exposed to a lot of pesticide separately from your regular wash. /Residential users/

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

PESTICIDE DISPOSAL: Wastes resulting from the use of this product may be disposed of on sit or at an approved waste disposal facility. /Sinbar Herbicide/

CONTAINER DISPOSAL: Non refillable container. Do Not reuse or refill this container. Offer for recycling, if available. Completely empty bag into application equipment. Then dispose of empty bag in a sanitary landfill or by incineration, or, if allowed by State and local authorities, by burning. If burned, stay out of smoke. /Sinbar Herbicide/

For more Disposal Methods (Complete) data for TERBACIL (7 total), please visit the HSDB record page.

Use this product only in accordance with its labeling and with the Worker Protection Standard, 40 CFR part 170. /Sinbar Herbicide/

Do not apply this product in a way that will contact workers or other persons, either directly or through drift. Only protected handlers may be in the area during application. /Sinbar Herbicide/

User should: Wash hands before eating, drinking, chewing gum, using tobacco or using the toilet. Users should remove clothing/PPE immediately if pesticide gets inside. Then wash thoroughly and put on clean clothing. Users should remove PPE immediately after handling this product. As soon as possible, wash thoroughly and change into clean clothing. /Sinbar Herbicide/

Do not apply directly to water, to areas where surface water is present or to intertidal areas below the mean high water mark. /Sinbar Herbicide/

For more Preventive Measures (Complete) data for TERBACIL (16 total), please visit the HSDB record page.

Tolerances are established for combined residues of the herbicide terbacil, (3-tert-butyl-5-chloro-6-methyluracil) and its metabolites [3-tert-butyl-5-chloro-6-hydroxymethyluracil], [6-chloro-2,3-dihydro-7-hydroxymethyl 3,3-dimethyl-5H-oxazolo(3,2-a) pyrimidin-5-one], and [6-chloro-2,3-dihydro-3,3,7-trimethyl-5H-oxazolo(3,2-a) pyrimidin-5-one], calculated as terbacil, in or on the following raw agricultural commodities: [Table#3140]

Applicators and other handlers must wear: Long-sleeved shirt and long pants. Chemical-resistant gloves made of any waterproof material such as polyethylene or polyvinyl chloride. Shoes plus socks. /Sinbar Herbicide/

... Restricted entry interval (REI) of 12 hours. PPE required for early entry to treated areas that is permitted under the Worker Protection Standard and that involves contact with anything that has been treated, such as plants, soil, or water, is: Coveralls. Chemical-resistant gloves made of any waterproof material. Shoes plus socks. /Sinbar Herbicide/

When handlers use closed systems, enclosed cabs or aircraft in a manner that meets the requirements listed in the Worker Protection Standard (WPS) for agricultural pesticides [40 CFR 170.240 (d)(4-6)], the handler PPE requirements may be reduced or modified as specified in the WPS. /Sinbar Herbicide/

Chemical-resistant gloves.

LC50; Species: Anas platyrhynchos (Mallard Duck, juvenile) diet >5000 ppm for 8 days

LC50; Species: Anas platyrhynchos (Mallard Duck, age 5-6 days) diet >56200 ppm for 8 days

LC50; Species: Phasianus colchicus (Ring-Necked Pheasant, juvenile) diet 26426 ppm for 8 days

LD50; Species: Colinus virginianus (Northern Bobwhite Quail, age 24 wk) oral via capsule >2250 mg/kg organism

For more Ecotoxicity Values (Complete) data for TERBACIL (14 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 41 to 89(2-5), indicate that terbacil is expected to have very high to high mobility in soil(SRC). Volatilization of terbacil from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.9X10-10 atm-cu m/mole(SRC), based upon its vapor pressure, 4.7X10-7 mm Hg(6), and water solubility, 710 mg/L(7). Terbacil is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(6). Based on soil biodegradation studies where terbacil has reported half-lives of 60(8) to 653 days(2) under aerobic conditions and 235 days(2) under anaerobic conditions, biodegradation of terbacil is expected to be very slow(SRC). Extrapolated first-order photodegradation half-lives of 46 and 61 days have been reported(2).

TERRESTRIAL FATE: Terbacil was lost from orchard soil by degradation and leaching. The time required for loss of 50% in soil concentration was 5-7 months.

AQUATIC FATE: Based on a classification scheme(1), Koc values of 41 to 89(2-5), indicate that terbacil is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(6) based upon an estimated Henry's Law constant of 1.9X10-10 atm-cu m/mole(SRC), derived from its vapor pressure, 4.7X10-7 mm Hg(7), and water solubility, 710 mg/L(8). According to a classification scheme(9), a BCF of 6(10), measured in bluegill, suggests the potential for bioconcentration in aquatic organisms is low(SRC). Based on soil biodegradation studies where terbacil exhibited reported half-lives of 60(11) to 653 days(2) under aerobic conditions and 235 days(2) under anaerobic conditions, biodegradation of terbacil is expected to be very slow(SRC). Terbacil is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). Radio-labeled terbacil, under natural sunlight, exhibited first-order photodegradation half-lives of 29 days in laboratory water, 37 days in river water (Brandywine River) and 54 days in water with suspended sediment (Brandywine River)(2).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), terbacil, which has a vapor pressure of 4.7X10-7 mm Hg at 29.5 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase terbacil is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 51 hours(SRC), calculated from its rate constant of 7.5X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Vapor-phase terbacil is also degraded in the atmosphere by reaction with ozone(SRC); the half-life for this reaction in air is estimated to be 7 days(SRC), calculated from its rate constant of 1.6X10-18 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase terbacil may be removed from the air by wet or dry deposition(SRC). Terbacil contains chromophores that absorb at wavelengths >290 nm(4) and therefore may be susceptible to direct photolysis by sunlight(SRC).

Groundwater: Using the maximum groundwater concentration of 0.0089 mg/L an estimated daily intake, assuming 2 L/day of water, is 0.00025 mg terbacil/kg body wt/day for an adult, assuming 1 L/day of water, is 0.00089 mg terbacil/kg body wt/day for a 10 kg child; Surface water: Using the maximum concentration of 0.105 ug/L found near sugar cane fields an estimated daily intake, assuming 2 L/day of water, is 0.003 mg terbacil/kg body wt/day for an adult, assuming 1 L/day of water, is 0.00105 mg terbacil/kg body wt/day for a 10 kg child(1).

/AQUATIC SPECIES/ Aquatic toxicity (TLm 48 hr, tlm= median tolerance limit): sunfish 86 ppm, carp greater than 10 (rank a--lowest toxicity category of materials tested); water flea greater than 0.5 (rank a--lowest toxicity category of materials tested); grass shrimp 42 ppm; fiddler crab 1000 ppm (highest concn tested); oyster larvae 4.9 ppm (highest concn tested). Wildlife lc50 (8-day oral): pheasant 31,450 ppm. /from table/

Levels and total discharge of terbacil after application at rate of 4.5 kg/ha to field at Fort Pierce, FL, were measured in drainage water for 13 days. Overflow water vol highest in surface tillage (st) plots. Only 1-2% of amt applied was detected in drainage waters.

Terbacil

Endocrine

1.3 x 10 ^-2 mg/kg-day

The Koc of terbacil ranges from 41 to 89(1-4). According to a classification scheme(5), these Koc values suggest that terbacil is expected to have high to very high mobility in soil(SRC). Radio-labeled terbacil (0.3-6.3 ug/mL) had a Freundlich adsorption coefficient of 0.39 ml/g (Koc = 61) in Woodstown sandy loam, 0.71 mL/g (Koc = 58) in Cecil sandy loam; 1.3 mL/g (Koc = 52), 1.2 mL/g (Koc = 44) in a Keyport silt loam(1). Radio-labeled terbacil had Freundlich adsorption coefficient of 2.46 mL/g (Koc = 64) in a Webster silty clay loam, 0.38 mL/g (Koc = 42) in a Cecil sandy loam, 0.38 mL/g (Koc = 76) in a Glendale sandy clay loam, and 0.12 mL/g (Koc = 21) in Eustis fine sand(1). Radio-labeled terbacil, at 1 ug/mL, had Freundlich adsorption coefficients ranging from 0.7-1.6 mL/g (Koc = 58-85) for twelve mineral soils(1).

URBAN/SUBURBAN: Terbacil was not detected in 24 urban air samples from a South Jackson residential area of Hinds County, MS(1). All samples were taken April to September, 1995(1).

RURAL/REMOTE: Terbacil was not detected in 21 agricultural air samples from Rolling Fork, MS(1). All samples were taken April to September, 1995(1).

Terbacil, present at 100 ppm, biodegraded 20% after 32 weeks in an aerobic sandy loam soil at 23 °C(1). In an aerobic loam soil at 32 °C, 8 ppm terbacil exhibited a half-life of about 5 months(1). Half-lives of 2-3 months were observed for 2 ppm terbacil in aerobic silt loam and sandy loam soils(1). At an initial concentration of 2.88 ppm, 28% biodegradation was observed for radio-labeled terbacil (unspecified placement of the label) after 600 days in an aerobic sandy loam soil(2); in the same study, only a trace amount of the 2.88 ppm terbacil (unspecified placement of the label) biodegraded in an anaerobic sandy loam after 145 days(2). Furthermore, 2.1 ppm terbacil degraded <5% in anaerobic silt loam and sandy soil after 60 days at 20 °C in the dark(1). After 90 days of incubation in sterile and nonsterile soils, at least 90% of 2 ppm terbacil remained; 0.8-1.5% of applied 14C evolved as CO2 from nonsterile soil, whereas 0.01% was evolved from sterile soil(1). Therefore, terbacil is only slowly metabolized by microbes in soil.

AEROBIC: Radio-labeled terbacil (9.3 ug/g) had a first-order half-life of 653 days (extrapolated) in a sassafras sandy loam soil when incubated for 12 months at 25 °C in the dark(1). The major transformation product (>10% of applied) was 14-carbon dioxide. Minor transformation products (<10% of applied) were t-butylurea and 3-tert-butyl-6-methyluracil. In an ancillary study, radio-labeled terbacil had a half-life of 2 to 3 months in nonsterile soils (Fallsington sandy loam and Flanagan silt loam) when incubated in a greenhouse(1).

ANAEROBIC: Radio-labeled terbacil, at 9.3 ug/g, had a first-order half-life of 235 days (extrapolated) when incubated for 90 days in anaerobic sassafras sandy loam soil at 25 C in the dark. Minor transformation products (<10% of applied) were t-butylurea and 3-tert-butyl-5-chloro-6-hydroxymethyluracil. In an ancillary study, radio-labeled terbacil (2.1 ug/g) had a half-life of >60 days when incubated for 60 days in anaerobic mineral soils (Fallsington and Flanagan) under greenhouse conditions(1).

Tolerances are established for combined residues of the herbicide terbacil, (3-tert-butyl-5-chloro-6-methyluracil) and its metabolites [3-tert-butyl-5-chloro-6-hydroxymethyluracil], [6-chloro-2,3-dihydro-7-hydroxymethyl 3,3-dimethyl-5H-oxazolo(3,2-a) pyrimidin-5-one], and [6-chloro-2,3-dihydro-3,3,7-trimethyl-5H-oxazolo(3,2-a) pyrimidin-5-one], calculated as terbacil, in or on the following raw agricultural commodities: [Table#3141]

Based on the reviews of the generic data for the active ingredient terbacil, the Agency has sufficient information on the health effects of terbacil and on its 78 potential for causing adverse effects in fish, wildlife, and the environment. The Agency has determined that terbacil products, labeled and used as specified in this Reregistration Eligibility Decision, will not pose unreasonable risks or adverse effects to humans or the environment. Under the Food Quality Protection Act of 1996, the Agency has determined that a reasonable certainty of no harm will result to infants and children or to the general population from aggregate exposure to terbacil. Therefore, the Agency concludes that products containing terbacil for all uses are eligible for reregistration.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their continued use. Under this pesticide reregistration program, EPA examines newer health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether the use of the pesticide does not pose unreasonable risk in accordance to newer saftey standards, such as those described in the Food Quality Protection Act of 1996. Terbacil is found on List A, which contains most pesticides that are used on foods and, hence, have a high potential for human exposure. List A consists of the 194 chemical cases (or 350 individual active ingredients) for which EPA issued registration standards prior to FIFRA '88. Case No: 0039; Pesticide type: herbicide; Registration Standard Date: 09/12/89; Case Status: RED Approved 09/97; OPP has made a decision that some/all uses of the pesticide are eligible for reregistration, as reflected in a Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): Terbacil; Data Call-in (DCI) Date(s): 03/03/95, 10/13/95; AI Status: OPP has completed a Reregistration Eligibility Decision (RED) document for the case/AI.

... Beagle dogs ... fed diets containing terbacil. ... Main metabolite /in urine/ was 3-tert-butyl-5-chloro-6-hydroxymethyluracil. ... Other/s/ ... observed: 6-chloro-2,3-dihydro-7-(hydroxymethyl)-3,3-dimethyl-5h-oxazolo- (3,2-a)pyrimidin-5-one; 6-chloro-2,3-dihydro-3,3,7-trimethyl- 5H-oxazolo(3,2-a)pyrimidin-5-one; 3-tert-butyl-6-hydroxymethyluracil /&/ 3-tert-butyl-6-formyluracil ... .

Terbacil is metabolized to 3-tert-butyl-5-chloro-6-(hydroxymethyl) uracil, excreted in dogs fed with a diet incorporating terbacil.

Oxidation of a methyl group and the tert-butyl group gives the oxidative products of terbacil, which are than cyclized to form an oxazolidine ring.

Orange seedlings were grown in solutions containing (14)C-terbacil. Analysis of plant tissues showed the presence of the 6-hydroxymethyl analog and a conjugate believed to be the beta-glucoside.

For more Metabolism/Metabolites (Complete) data for TERBACIL (7 total), please visit the HSDB record page.

Used as selective herbicide for control of annual and some perennial weeds; [HSDB]

Farming (Pesticides) [Category: Industry]

For terbacil (USEPA/OPP Pesticide Code: 012701) ACTIVE products with label matches. /SRP: Registered for use in the U.S. but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Herbicides (uracil herbicides)

Used for selective control of many annual and some perennial weeds

Herbicide

Terbacil is produced by reaction of tert-butyl isocyanate with methyl 3-aminocrotonate, followed by cyclization and chlorination.

Terbacil may be made by the chlorination of 3-tert-butyl-6-methyluracil.

t-Butylamine + sodium cyanate + ethyl acetoacetate + chlorine (cyanate addition/condensation/chlorination)

Wettable powder

Composition: Technical is 97%

Sinbar Herbicide (Tessenderlo Kerley, Inc.) 80% Terbacil

Terbacil Technical Herbicide (Tessenderlo Kerley, Inc.) 97.5% Terbacil

For more Formulations/Preparations (Complete) data for TERBACIL (7 total), please visit the HSDB record page.