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TopChoice Insecticide Dangers

By Frank Whittemore ; Updated September 21, 2017

TopChoice is a popular insecticide that is commonly used as a treatment for pests, such as fire ants, mole crickets, fleas and ticks. It is a long-lasting, granular insecticide, which eliminates insects by interfering with their nervous system. The active ingredient of TopChoice is a chemical known as Fipronil, which is currently both an EPA and California State registered insecticide. Care should be taken when you use TopChoice, as there are some risks inherent in this insecticide.

Toxicity Information

The World Health Organization (WHO) has identified Fipronil as a Class II toxin and considers the chemical moderately hazardous. The United States Environmental Protection Agency lists it as a Category 2 chemical, considering Fipronil to be moderately toxic. The EPA requires a warning to that effect to be listed on the label of TopChoice packaging. Symptoms of exposure to Fipronil in humans include nausea, dizziness, headache and weakness. Pets may demonstrate lethargy, a lack of coordination and convulsions.

Endocrine Disruptor

Some insecticides interfere with the function of the endocrine system and the release and regulation of estrogen, androgen and thyroid hormones. Exposure can cause decreased fertility or even sterility, and impaired fetal development and birth defects.

Fipronil, has been identified on the Colburn list, a study performed by researcher Theo Colburn in 1993, as being a potential endocrine disruptor. The European Union Prioritization List, published in December of 1999, also indicates that Fipronil should be considered an endocrine disrupting chemical.

Cancer Risk

The United States Environmental Protection Agency lists Fipronil as a Category C carcinogen on their list of chemicals evaluated for carcinogenic potential. This list is developed to evaluate any data available concerning a specific chemical's risk of causing cancer and then report the findings to the EPA. In the case of Fipronil, there is some limited evidence to indicate that the chemical may be carcinogenic.


The Pesticide Action Network indicates that Fipronil does have the potential to contaminate groundwater. This is based on water solubility, the absorption coefficient of the chemical and the half-life of the chemical within the soil. In aquatic environments, Fipronil is also very highly toxic to plankton, insects and crustaceans. It is highly toxic to fish. The chemical is also very toxic to reptiles and amphibians, some birds and honey bees.


TopChoice can be considered an irritant to both skin and eyes. The chemical can cause severe irritation to the skin resulting in redness and swelling. Exposure to the eyes will cause corneal irritation that can last from one to three weeks.


About the Author


In Jacksonville, Fla., Frank Whittemore is a content strategist with over a decade of experience as a hospital corpsman in the U.S. Navy and a licensed paramedic. He has over 15 years experience writing for several Fortune 500 companies. Whittemore writes on topics in medicine, nature, science, technology, the arts, cuisine, travel and sports.