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Fipronil

Technical Fact Sheet

As of 2011, NPIC stopped creating technical pesticide fact sheets. The old collection of technical fact sheets will remain available in this archive, but they may contain out-of-date material. NPIC no longer has the capacity to consistently update them. To visit our general fact sheets, click here. For up-to-date technical fact sheets, please visit the Environmental Protection Agency’s webpage.

Molecular Structure -
Fipronil

Laboratory Testing: Before pesticides are registered by the U.S. EPA, they must undergo laboratory testing for short-term (acute) and long-term (chronic) health effects. Laboratory animals are purposely given high enough doses to cause toxic effects. These tests help scientists judge how these chemicals might affect humans, domestic animals, and wildlife in cases of overexposure.

Chemical Class and Type:

Physical / Chemical Properties:

Uses:

Mode of Action:

Target and Non-target Organisms

Acute Toxicity:

Oral

Dermal

TOXICITY CLASSIFICATION - FIPRONIL
High Toxicity Moderate Toxicity Low Toxicity Very Low Toxicity
Acute Oral LD50 Up to and including 50 mg/kg
(≤ 50 mg/kg)
Greater than 50 through 500 mg/kg
(>50-500 mg/kg)
Greater than 500 through 5000 mg/kg
(>500-5000 mg/kg)
Greater than 5000 mg/kg
(>5000 mg/kg)
Inhalation LC50 Up to and including 0.05 mg/L
(≤0.05 mg/L)
Greater than 0.05 through 0.5 mg/L
(>0.05-0.5 mg/L)
Greater than 0.5 through 2.0 mg/L
(>0.5-2.0 mg/L)
Greater than 2.0 mg/L
(>2.0 mg/L)
Dermal LD50 Up to and including 200 mg/kg
(≤200 mg/kg)
Greater than 200 through 2000 mg/kg
(>200-2000 mg/kg)
Greater than 2000 through 5000 mg/kg
(>2000-5000 mg/kg)
Greater than 5000 mg/kg
(>5000 mg/kg)
Primary Eye Irritation Corrosive (irreversible destruction of ocular tissue) or corneal involvement or irritation persisting for more than 21 days Corneal involvement or other eye irritation clearing in 8 - 21 days Corneal involvement or other eye irritation clearing in 7 days or less Minimal effects clearing in less than 24 hours
Primary Skin Irritation Corrosive (tissue destruction into the dermis and/or scarring) Severe irritation at 72 hours (severe erythema or edema) Moderate irritation at 72 hours (moderate erythema) Mild or slight irritation at 72 hours (no irritation or erythema)
The highlighted boxes reflect the values in the "Acute Toxicity" section of this fact sheet. Modeled after the U.S. Environmental Protection Agency, Office of Pesticide Programs, Label Review Manual, Chapter 7: Precautionary Labeling. http://www.epa.gov/oppfead1/labeling/lrm/chap-07.pdf

Inhalation

Signs of Toxicity - Animals

Signs of Toxicity - Humans

Chronic Toxicity:

Animals

Humans

Exposure: Effects of fipronil on human health and the environment depend on how much fipronil is present and the length and frequency of exposure. Effects also depend on the health of a person and/or certain environmental factors.

Endocrine Disruption:

Carcinogenicity:

Animals

Cancer: Government agencies in the United States and abroad have developed programs to evaluate the potential for a chemical to cause cancer. Testing guidelines and classification systems vary. To learn more about the meaning of various cancer classification descriptors listed in this fact sheet, please visit the appropriate reference, or call NPIC.

Humans

Reproductive or Teratogenic Effects:

Animals

Humans

Fate in the Body:

Absorption

Distribution

Metabolism

Excretion

Medical Tests and Monitoring:

The "half-life" is the time required for half of the compound to break down in the environment.

1 half-life = 50% remaining
2 half-lives = 25% remaining
3 half-lives = 12% remaining
4 half-lives = 6% remaining
5 half-lives = 3% remaining

Half-lives can vary widely based on environmental factors. The amount of chemical remaining after a half-life will always depend on the amount of the chemical originally applied. It should be noted that some chemicals may degrade into compounds of toxicological significance.

Environmental Fate:

Soil

Water

Air

Plants

Indoor

Food Residue

Ecotoxicity Studies:

Birds

Fish and Aquatic Life

Terrestrial Invertebrates

Regulatory Guidelines:

Date Reviewed: January 2009

Please cite as: Jackson, D.; Cornell, C. B.; Luukinen, B.; Buhl, K.; Stone, D. 2009. Fipronil Technical Fact Sheet; National Pesticide Information Center, Oregon State University Extension Services. http://npic.orst.edu/factsheets/archive/fiptech.html.

References:

  1. Tomlin, C. D. S. The Pesticide Manual, A World Compendium, 14th ed.; British Crop Protection Council: Hampshire, England, 2006; pp 462-464.
  2. New Pesticide Fact Sheet - Fipronil; EPA 737-F-96-005; U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, U.S. Government Printing Office Washington, DC, 1996; pp 1-10.
  3. Ying, G. G.; Kookana, R. S. Sorption of Fipronil and Its Metabolites on Soils From South Australia. J. Environ. Sci. Health 2001, B36 (5), 545-558.
  4. Pesticide Products. Pest-Bank [CD-ROM] 2007.
  5. Cole, L. M.; Nicholson, R. A.; Casida, J. E. Action of Phenylpyrazole Insecticides at the GABA-Gated Chloride Channel. Pestic. Biochem. Physiol. 1993, 46, 47-54.
  6. Ratra, G. S.; Casida, J. E. GABA receptor subunit composition relative to insecticide potency and selectivity. Toxicol. Lett. 2001, 122, 215-222.
  7. WHO. Pesticide Residues in Food - 1997: Fipronil; International Programme on Chemical Safety, World Health Organization: Lyon, 1997.
  8. Hainzl, D.; Cole, L. M.; Casida, J. E. Mechanisms for Selective Toxicity of Fipronil Insecticide and Its Sulfone Metabolite and Desulfinyl Photoproduct. Chem. Res. Toxicol. 1998, 11, 1529-1535.
  9. Ratra, G. S.; Kamita, G. S.; Casida, J. E. Role of Human GABAA Receptor B3 Subunit in Insecticide Toxicity. Toxic. Appl. Pharmacol. 2001, 172, 233-240.
  10. Zhao, X.; Yeh, J. Z.; Salgado, V. L.; Narahashi, T. Sulfone metabolite of fipronil blocks gamma-aminobutyric acid- and glutamate-activated chloride channels in mammalian and insect neurons. J. Pharmacol. Exp. Ther. 2005, 314 (1), 363-73.
  11. Hainzl, D.; Casida, J. E. Fipronil insecticide: Novel photochemical desulfinylation with retention of neurotoxicity. Proc. Natl. Acad. Sci. 1996, 93, 12764-12767.
  12. Fipronil: Third Reevaluation - Report of the Hazard Identification Assessment Review Committee; HED Doc. No. 014400; U.S. Environmental Protection Agency, Health Effects Division, U.S. Government Printing Office: Washington, DC, 2000; pp 1-24.
  13. Dange, M. Acute Oral LD50 in Rats. Unpublished Report No. SA 93074. Submitted to the World Health Organization by Rhone-Poulenc, Inc.: Research Triangle Park, NC, 1994.
  14. Kamijima, M.; Casida, J. E. Regional Modification of [3H] Ethynylbicycloorthobenzoate Binding in Mouse Brain GABAA Receptor by Endosulfan, Fipronil, and Avermectin B1a. Toxicol. Appl. Pharmacol. 2000, 163, 188-194.
  15. Fung, H. T.; Chan, K. K.; Ching, W. M.; Kam, C. W. A Case of Accidental Ingestion of Ant Bait Containing Fipronil. J. Toxicol. Clin. Toxicol. 2003, 41 (3), 245-248.
  16. Jennings, K. A.; Keller, R. J.; Doss, R. B. Human Exposure to Fipronil from Dogs Treated with Frontline. Controv. Toxicol. 2002, 44 (5), 301-303.
  17. Mohamed, F.; Senarathna, L.; Percy, A.; Abeyewardene, M.; Eaglesham, G.; Cheng, R.; Azher, S.; Hittarage, A.; Dissanayake, W.; Sheriff, M. H. R.; Davies, W.; Buckley, N. A.; Eddleston, M. Acute Human Self-poisoning with the N-Phenylpyrazole Insecticide Fipronil--a GABAA-Gated Chloride Channel Blocker. J. Toxicol. Clin. Toxicol. 2004, 42 (7), 955-963.
  18. Chodorowski, Z., M.D., Ph.D.; Anand, J. S., M.D., Ph.D. Accidental Dermal and Inhalation Exposure with Fipronil--A Case Report. J. Toxicol. Clin. Toxicol. 2004, 42 (2), 189-190.
  19. WHO. Pesticide Residues in Food 2000: Fipronil (addendum); International Programme on Chemical Safety, World Health Organization: Geneva, Switzerland, 2002.
  20. Fipronil; Notice of Filing a Pesticide Petition to Establish a Tolerance for a Certain Pesticide Chemical in or on Food. Fed. Regist. August 24, 2005, 70 (163), 49599-49607.
  21. Food and Environment Protection Act 1985, Part III, Control of Pesticides Regulations 1986, Evaluation of Fully Approved or Provisionally Approved Products: Evaluation on Fipronil (Horticultural Uses); No. 212; Department for Environment, Food and Rural Affairs, Pesticide Safety Directorate: York, England, 2004; pp 1-239.
  22. Birckel, P.; Cochet, P.; Benard, P.; Weil, A. Cutaneous Distribution of 14C-Fipronil in the Dog and in the Cat Following a Spot-On Administration; Third World Congress of Veterinary Dermatology: Edinburgh, Scotland, 1996.
  23. CDC. Third National Report on Human Exposure to Environmental Chemicals; U.S. Department of Health and Human Services, Centers for Disease Control and Prevention: Atlanta, 2005.
  24. Bobe, A.; Meallier, P.; Cooper, J. F.; Coste, C. M. Kinetics and Mechanisms of Abiotic Degradation of Fipronil (Hydrolysis and Photolysis). J. Agric. Food Chem. 1998, 46, 2834-2839.
  25. Ying, G.; Kookana, R. S. Persistence and movement of fipronil termiticide with under-slab and trenching treatments. Environ. Toxicol. Chem. 2006, 25 (8), 2045-2050.
  26. Ngim, K. K.; Crosby, D. G. Abiotic Processes Influencing Fipronil and Desthiofipronil Dissipation in California, USA, Rice Fields. Environ. Toxicol. Chem. 2000, 20 (5), 972-977.
  27. Fipronil and Degradation Products in the Rice-Producing Areas of the Mermentau River Basin, Louisiana, February- September 2000; USGS Fact Sheet FS-010-0; U.S. Department of the Interior, U.S Geological Survey. http://la.water.usgs.gov/publications/pdfs/FS-010-03.pdf (accessed Oct 2007) updated March 2003.
  28. Food and Drug Administration Pesticide Program Residue Monitoring 1993-2003; U.S Food and Drug Administration, Center for Food Safety and Applied Nutrition: Silver Springs, MD, 2005.
  29. Pesticide Data Program Annual Summary, Calendar Year 2006; U.S. Department of Agriculture, Agricultural Marketing Service, Science and Technology Programs: Washington, DC, 2007.
  30. Pesticide Data Program Annual Summary Reports for Downloading, Viewing, and Printing; U.S. Department of Agriculture, Agricultural Marketing Service, Pesticide Data Program. http://www.ams.usda.gov (accessed June 2008) updated Jan 2008.
  31. Cary, T. L.; Chandler, G. T.; Volz, D. C.; Walse, S. S.; Ferry, J. L. Phenylpyrazole Insecticide Fipronil Induces Male Infertility in the Estuarine Meiobenthic Crustacean Amphiascus tenuiremis. Environ. Sci. Technol. 2004, 38 (2), 522-528.
  32. Chaton, P. F.; Ravanel, P.; Tissut, M.; Meyran, J. C. Toxicity and Bioaccumulation of Fipronil in the Nontarget Arthropodan Fauna Associated with Subalpine Mosquito Breeding Sites. Ecotoxicol. Environ. Saf. 2001, 52, 8-12.
  33. Elzen, G. W. Lethal and Sublethal Effects of Insecticide Residues on Orius insidiosus (Hemiptera: Anthocoridae) and Geocoris punctipes (Hemiptera: Lygaeidae). J. Econ. Entomol. 2001, 94, 55-59.
  34. Balanca, G.; de Visscher, M.-N. Impacts on Nontarget Insects of a New Insecticide Compound used Against the Desert Locust (Schistocerca gregaria (Forskal 1775)). Arch. Environ. Contam. Toxicol. 1997, 32, 58-62.
  35. Mostert, M. A.; Schoeman, A. S.; Van der Merwe, M. The relative toxicities of insecticides to earthworms of the Pheretima group (Oligochaeta). Pest Manag. Sci. 2002, 58, 446-450.
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