Oxadiazon
HERBICIDE FACT SHEET
U.S. DEPARTMENT OF ENERGY
BONNEVILLE POWER ADMINISTRATION
This fact sheet is one of a series issued by the Bonneville Power Administration for their workers and the
general public. It provides information on forest and land management uses, environmental and human
health effects, and safety precautions. A list of definitions is included in Section VIII of this fact sheet.
I. BASIC INFORMATION
COMMON NAME: oxadiazon
CHEMICAL NAME: [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-2-1,3,4-oxadiazoline-5-one]
Cas No. 19666-30-9
CHEMICAL TYPE: oxadiazole
PESTICIDE CLASSIFICATION: herbicide
REGISTERED USE STATUS: General Use Pesticide.
FORMULATIONS: Commercial herbicide products generally contain one or more ingredients. An inert
ingredient is anything added to the product other than an active ingredient. Because of concern for
human health and the environment, EPA announced its policy on toxic inert ingredients in the Federal
Register on April 22, 1987 (52FR13305). This policy focuses on the regulation of inert ingredients.
EPA's strategy for implementing this policy included the development of four lists of inerts, based on
toxicological concerns. Inerts of toxicological concern were placed on List 1. Potentially toxic inerts/high
priority for testing were placed on List 2. Inerts of unknown toxicity were placed on List 3, and inerts of
minimal and no concern were placed on List 4A and 4B, respectively.
The contents of the oxadiazon formulation for Ronstar?AC and G herbicide are listed below:
Ronstar?AC Herbicide (Regal Chemical Company) No inert ingredients listed.
Ronstar?G Herbicide (Bayer Environmental Science)
Active Ingredient oxadiazon 2.0 %
Inert Ingredients 98.0 %
RESIDUE ANALYTICAL METHODS: Standard herbicide screening analysis.
1
II. HERBICIDE USES
REGISTERED FORESTRY, RANGELAND AND RIGHT-OF-WAY USES: Oxadiazon is registered for
weed control by commercial nursery, turf, and landscape personnel only. For terrestrial use only.
OPERATIONAL DETAILS:
TARGET PLANTS: selective pre-emergent herbicide for control of annual grasses, broadleaf weeds,
vines, and brambles.
MODE OF ACTION: Inhibits enzyme protoporphyrinogen oxidase.
METHOD OF APPLICATION AND RATES: Ground application via granular applicator. Rates
adjustable between 2.25 lb and 4.5 lb per 1000 sq ft..
SPECIAL PRECAUTIONS:
TIMING OF APPLICATION: Timing is dependent on the target plant and desired results. Weed
management is best obtained with lat summer to early spring applications.
DRIFT CONTROL: Care should be exercised not to over-applicate or apply the herbicide to adjacent
non-target areas. Drift control is achieved by observing weather conditions and following label and
granulator applicator instructions.
Restrictions/Warnings/Limitations:
T&E toxicity warning for ALL plants.
T&E toxicity warning for aquatic species.
Surface water warning.
Do not use on food or feed crops.
Do not use on areas to be grazed or cut for hay.
Do not use the product to treat irrigation ditches or other channels used for either agricultural or
domestic purposes
Do not apply this herbicide via any type of irrigation system.
Do not apply to the foliage of desirable trees or ornamental plants.
2
III. ENVIRONMENTAL EFFECTS/FATE
SOLUBILITY: 0.7 mg/l in water (pH 7 at 20?C).
VAPOR PRESSURE: 7.76 x 10-7 mm Hg.
HYDROLYSIS: Stable.
PHOTOLYSIS IN WATER: 3 days.
PHOTOLYSIS ON SOIL: NA.
AEROBIC SOIL METABOLISM: AVERAGE: 60 days.
ANAEROBIC SOIL METABOLISM: Information not available.
KOC: 1409-3268 Depending on soil
PERSISTENCE AND AGENTS OF DEGRADATION/DISSIPATION: The primary route of dissipation is
photolysis.
METABOLITES/DEGRADATION PRODUCTS AND POTENTIAL ENVIRONMENTAL EFFECTS: None
POTENTIAL FOR LEACHING INTO SURFACE AND GROUND WATER: There is moderate potential for
surface water leaching due to the high KOC and moderate half-life. There is low potential to leach into
ground water for the same reasons.
POTENTIAL FOR BYPRODUCTS FROM BURNING OF TREATED VEGETATION: Information not
available.
IV. ECOLOGICAL TOXICITY EFFECTS ON NON-TARGET SPECIES
TERRESTRIAL:
AVIAN ACUTE ORAL TOXICITY: LD50 (mallard duck) >1040 mg/kg
AVIAN SUBACUTE DIETARY TOXICITY: LC50 (mallard duck) >5000 mg/kg
LD50 (bobwhite quail) >5000 mg/kg
SMALL MAMMAL ACUTE ORAL TOXICITY: LD50 (rat) 3500 to >5000 mg/kg
OVERALL TERRESTRIALTOXICITY: SlightlyToxic
PLANTS: Contact will injure or kill target and non-target plants.
3
FRESHWATER AQUATIC SPECIES:
ACUTE TOXICITY: LC50 (rainbow trout 96-hour) 0.88 mg/l
ACUTE TOXICITY: LC50 (bluegill sunfish 96-hour) 0.88mg/l
ACUTE TOXICITY: EC50 (Daphnia 48-hour) 2.2 mg/l
OVERALL FRESHWATER AQUATIC TOXICITY: Highly Toxic
ESTUARINE/MARINE AQUATIC SPECIES:
ACUTE TOXICITY: LC50 (sheepshead minnow 96-hour) 1.5 mg/l
ACUTE TOXICITY: LC50 (mysid shrimp 96-hour) 2.7 mg/l
OVERALL ESTUARINE/MARINE TOXICITY: Moderately Toxic
BIOACCUMULATION POTENTIAL: Very low to none.
THREATENED AND ENDANGERED SPECIES: Federally listed terrestrial and aquatic plants, as well as,
freshwater and marine aquatic species may be adversely affected if the product is applied directly to
plants and surface water.
V. TOXICOLOGICAL DATA
ACUTE TOXICITY:
ACUTE ORAL TOXICITY: LD50 (rat) >5000 mg/kg
ACUTE DERMAL TOXICITY: LD50 (rabbit) >2000 mg/kg
ACUTE INHALATION: LC50 (rat 4-hour) >2000 mg/l
OVERALL TOXICITY: Category III ?Slightly Toxic
CHRONIC TOXICITY:
CARCINOGENICITY: Positive (CA Prop 65 List).
DEVELOPMENTAL/REPRODUCTIVE: Positive (CA Prop 65 List).
MUTAGENICITY: Negative.
HAZARD: The end-use product labels for the oxadiazon formulation Ronstar?AC and Ronstar?G
herbicide carries the Warning signal word due to moderate eye and skin irritation.
4
VI. HUMAN HEALTH EFFECTS
ACUTE TOXICITY (POISONING):
REPORTED EFFECTS: None reported.
CHRONIC TOXICITY:
REPORTED EFFECTS: None reported.
POTENTIAL FOR ADVERSE HEALTH EFFECTS FROM CONTACTING OR CONSUMING TREATED
VEGETATION, WATER OR ANIMALS: Listed on CA Prop 65 List for carcinogenic and developmental
toxicity.
POTENTIAL FOR ADVERSE HEALTH EFFECTS FROM INERT INGREDIENTS CONTAINED IN THE
FORMULATED PRODUCTS: Listed on CA Prop 65 List for carcinogenic and developmental toxicity.
HEALTH EFFECTS OF EXPOSURE TO FORMULATED PRODUCTS: None reported.
HEALTH EFFECTS ASSOCIATED WITH CONTAMINANTS: None reported.
HEALTH EFFECTS ASSOCIATED WITH OTHER FORMULATIONS: None reported.
VII. SAFETY PRECAUTIONS
SIGNAL WORD AND DEFINITION:
OXADIAZON (Ronstar?AC and G Herbicide) - Warning ?HARMFUL IF INHALED, CAUSES
SKIN AND EYE IRRITATION
PROTECTIVE PRECAUTIONS FOR WORKERS: Applicators and other handlers must wear long-sleeved
shirt and long pants, shoes plus socks and gloves.
MEDICAL TREATMENT PROCEDURES (ANTIDOTES):
EYES: Flush eyes with water for 15 to 20 minutes. Call physician.
SKIN: Wash all exposed areas with soap and water, call physician if irritation is present.
INGESTION: Rinse mouth thoroughly with water. Do not induce vomiting. Call physician.
INHALATION: Remove to fresh air. Call a physician if breathing difficulty persists.
HANDLING, STORAGE AND DISPOSAL: Store at room temperature or cooler. Do not reuse container.
Rinse container and dispose accordingly. Do not store at home. Do not store around food or feed.
EMERGENCY SPILL PROCEDURES AND HAZARDS: Contain and sweep up material of small spills
and dispose as waste. Do not contaminate water, food, or feed by storage or disposal.
5
VIII. DEFINITIONS
adsorption ?the process of attaching to a surface
avian ?of, or related to, birds
CAEPA ?California Environmental Protection Agency
carcinogenicity ?ability to cause cancer
CHEMTREC ?Chemical Transportation Emergency Center
dermal ?of, or related to, the skin
EC50 - median effective concentration during a bioassay
ecotoxicological ?related to the effects of environmental toxicants on populations of organisms
originating, being produced, growing or living naturally in a particular region or environment
FIFRA ?Federal Insecticide, Fungicide and Rodenticide Act
formulation ?the form in which the pesticide is supplied by the manufacturer for use
half-life ?the time required for half the amount of a substance to be reduced by natural processes
herbicide ?a substance used to destroy plants or to slow down their growth
Hg ?chemical symbol for mercury
IARC ?International Agency for Research on Cancer
K(oc) ?the tendency of a chemical to be adsorbed by soil, expressed as: K(oc) = conc. adsorbed/conc.
dissolved/% organic carbon in soil
LC50 ?the concentration in air, water, or food that will kill approximately 50% of the subjects
LD50 ?the dose that will kill approximately 50% of the subjects
leach ?to dissolve out by the action of water
LOEC ?lowest observed effect concentration
mg/kg ?weight ratio expressed as milligrams per kilogram
mg/l ?weight-to-liquid ratio expressed as milligrams per liter
microorganisms ?living things too small to be seen without a microscope
mPa ?milli-Pascal (unit of pressure)
mutagenicity ?ability to cause genetic changes
NFPA ?National Fire Protection Association
NIOSH - National Institute for Occupational Safety and Health
NOEL - no observable effect level
non-target ?animals or plants other than the ones that the pesticide is intended to kill or control
OSHA - Occupational Safety and Health Administration
Pa ?Pascal (unit of pressure)
persistence ?tendency of a pesticide to remain to remain in the environment after it is applied
pesticides ?substances including herbicides, insecticides, rodenticides, fumigants, repellents, growth
regulators, etc., regulated under FIFRA
PPE ?personal protective equipment
ppm ?weight ratio expressed as parts per million
residual activity ?the remaining amount of activity as a pesticide
T&E ?Threatened and Endangered Species (from the Endangered Species Act)
g ?micrograms
volatility ?the tendency to become a vapor at standard temperatures and pressures
6
IX. INFORMATION SOURCES
Bayer Environmental Science, Ronstar?G Herbicide, Specimen Product Label, Ron G-SL-081303B, July
1998
Bayer Environmental Science, Ronstar?G Herbicide, Material Safety Data Sheet, MSDS Number 181,
Version 2.2, December 2002
California State, Environmental Protection Agency, Chemicals Known to the Sate to Cause Cancer or
Reproductive Toxicity, August 11, 2006
United States, Environmental Protection Agency, Reregistration Eligibility Decision for Oxadiazon, EPA
738-R-04-003, September 2003
Washington State, Department of Transportation, Oxadiazon Roadside Vegetation Management
Herbicide Fact Sheet, February 2006
7
X. TOXICITY CATEGORY TABLES
TABLE I: HUMAN HAZARDS
Category Signal Route of Administration Hazard
Word
Acute Oral Acute Dermal Acute Eye irritation Skin
LD50 LD50 (mg/kg) Inhalation irritation
(mg/kg) LC50 (mg/l)
I DANGER 0?0 0-200 0-0.2 corrosive: corrosive
(Highly (poison) corneal opacity
Toxic) not reversible
within 7 days
II WARNING >50?00 >200-2000 >0.2-2 corneal opacity severe
(Moderately reversible within irritation at 72
Toxic) 7 days; irritation hours
persisting for 7
days
III CAUTION >500-5000 >2000-20.000 >2-20 no corneal moderate
(Slightly opacity; irritation irritation at 72
Toxic) reversible within hours
7 days
IV NONE >5000 >20,000 >20 no irritation moderate
(Practically irritation at 72
Non-toxic) hours
After Pesticide User's Guide, Ohio State University, Extension Bull. No. 745, 1998.
TABLE II: ECOTOXICOLOGICAL RISKS TO WILDLIFE (TERRESTRIAL AND AQUATIC)
Risk Category Mammals Avian Avian Fish or Aquatic
Invertebrates
Acute Oral LD50 Acute Oral LD50 Acute Dietary LC50
mg/kg) (mg/kg) (mg/kg) Acute Concentration LC50
(mg/l)
Very Highly <10 <10 <50 <0.1
Toxic
Highly Toxic 10-50 10-50 50-500 0.1 ?1
Moderately 51-500 51-500 501-1,000 >1 ?10
Toxic
Slightly Toxic 501-2,000 501-2,000 1,001-5,000 >10 ?100
Practically >2,000 >2,000 >5,000 >100
Non-toxic
Table II created from information contained in Pesticides and Wildlife, Whitford, Fred, et al., Purdue University
Cooperative Extension Service PPP-30, 1998.
8
Disclaimers and Other Legal Information:
Mention of a trademark, vendor, technique, or proprietary product does not imply or constitute an
endorsement of the product by the United States Department of Energy - Bonneville Power
Administration (USDOE-BPA), its employees, and its contractors, and does not imply or endorse any
product to the exclusion of others. In all cases, the user is required by law to follow all pesticide label
instructions and restrictions.
This document is copyrighted by the USDOE-BPA. USDOE-BPA retains all rights under all conventions,
but permits free reproduction by all providing that full credit is given to USDOE-BPA in citing this
publication, sources and date of publication, and, that such reproduction is not distributed or redistributed
for profit.
This fact sheet was prepared by USDOE-Bonneville Power Administration, August 2006.
9
|