Smarter Living: Chemical Index

Tetrachlorvinphos (TCVP) is an organophosphate pesticide used to kill fleas and ticks. It is a likely human carcinogen and is toxic to the nervous system.

Health Concerns

TCVP interferes with an essential enzyme, acetylcholinesterase, which normally controls messaging between nerve cells. It kills fleas and ticks by inducing spasmodic overexcitation of the nervous system. In large doses, it can harm or kill cats, dogs and, in extreme poisoning cases, humans. At lower levels of exposure, TCVP cause a variety of poisoning symptoms, many of which can mimic common illnesses; these include nausea, vomiting, diarrhea, wheezing, sweating and tearing eyes. More severe poisoning can cause muscle twitching, drooling, seizures, respiratory paralysis and death.

Young children are also particularly vulnerable to TCVP and other pesticides because their bodies and brains are still developing, and chemicals that interfere with the nervous system during development may cause long-term or permanent damage. Some recent research indicates that exposure to this type of pesticide can impair children's neurological development, resulting in pervasive disorders that may include delays in motor development and attention deficit/ hyperactivity disorder.

Where it is Found

TCVP is used in pet flea and tick collars, shampoos and powders. Flea and tick collars can leave high levels of pesticide residue on a pet's fur, posing a health risk to adults and children who play with the pet. Children are especially vulnerable, as they may be more likely to spend extended time in close contact with pets, or put their hands in their mouths after petting an animal.

Stay Safe

Give your pet regular baths with a pesticide-free pet shampoo, and use a flea comb between baths. Launder your pet's bedding in hot water, and vacuum carpets regularly to eliminate flea eggs that could be hidden there. If you do need to use a chemical flea-control product, the safest options are generally those dispensed as a pill. These usually contain the least toxic chemicals, and they don't leave a residue on your pet or in your home. Check labels. If you do need to buy an off-the-shelf flea and tick product, avoid flea collars that list tetrachlorvinphos or propoxur as active ingredients. Other products to avoid include permethrin-based products and tick-control products containing amitraz or carbaryl. Instead, opt for safer products whose labels list lufenuron, spinosad, methoprene, or pyriproxyfen. These are common and effective insect growth regulators.Visit for an evaluation of brand-name products and the active chemicals they contain.

Take Action

Americans spend more than $1 billion each year on flea- and tick-control products for their pets, despite safety concerns. Over the years, NRDC has helped remove six of the most toxic chemicals from these products, but two of them--TCVP and propoxur--are still in use. The Environmental Protection Agency (EPA) should step in to ban these dangerous products nationwide. Retailers should help keep pets and families safe by pulling products that contain tetrachlorvinphos and propoxur from their shelves. You can help by going to to tell stores to protect our kids from dangerous products.

Learn More

How to Control Fleas Without Chemicals

Green Paws

last revised 12/28/2011

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