How Safe Is Termidor? Pets, Kids, Wells and Your Yard
Termidor is one of the most common termite treatments in the country, and the active ingredient is the same one in some flea drops. Here's what that means for your kids, your dog and the fish in the creek.
The short version
Applied by a licensed professional as the label directs, Termidor is considered low risk to people and pets once it dries. It's diluted to about a tenth of a percent fipronil and injected into soil, where it binds tightly. The label keeps residents, children and pets out of treated areas until sprays dry. It's highly toxic to fish, birds and bees.
On this page
What Termidor actually is
Termidor is a brand of termiticide whose active ingredient is fipronil, an insecticide first registered in the U.S. in 1996. The most common version for termites, Termidor SC, is a liquid concentrate that's 9.1 percent fipronil.
You'll never see the concentrate. A licensed applicator mixes it with water down to a finished solution of 0.06 to 0.125 percent fipronil, depending on the job, then puts it into the soil around and under your foundation by trenching, rodding and drilling through slabs.
The same active ingredient shows up in more than 50 registered products, including granular lawn products, gel baits and spot-on flea and tick treatments for pets. That doesn't make termite concentrate a pet product. It does tell you fipronil isn't some exotic chemical.
Why it's so effective on termites
Termidor is non-repellent. Older termite treatments worked like a fence that termites could sense and avoid, so they'd find the gaps. Termites can't detect fipronil, so they tunnel through treated soil, pick it up, and carry it back to the colony before it kills them.
Fipronil works on the insect nervous system. The National Pesticide Information Center explains that it's more toxic to insects than to people and pets because it binds more readily to insect nerve endings than to ours.
Who's at risk, and how much
Here's how the label and the National Pesticide Information Center describe the risks, translated into plain English.
| Who | Risk | What protects them |
|---|---|---|
| People and kids | Low once the treatment dries. Swallowing or heavy skin contact with wet product can cause irritation, nausea and worse | Stay out of treated areas until sprays dry, as the label requires |
| Dogs and cats | Low once dry. Wet treated soil and puddles are the risk | Keep pets inside or away from the foundation until it's dry, and fill in trenches |
| Fish and pond life | High. Fipronil is highly toxic to fish and aquatic invertebrates | Tell the applicator about ponds, creeks and drains before they start |
| Birds | High for some birds | Don't leave treated soil uncovered or spilled product around |
| Bees | High | Termite work goes into the soil, but say so if hives are nearby |
| Wells and cisterns | The label forbids applying within 5 feet of a well or cistern | Point out every well, cistern and spring before work begins |
| Earthworms | Not toxic, per the National Pesticide Information Center | Nothing to do |
What to do on treatment day
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Point out the water
Show the crew every well, cistern, pond, creek, storm drain and sump pump. The label has specific rules around wells and water, and a good applicator will ask anyway.
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Keep kids and pets in, or away
The label says not to allow residents, children and pets into treated areas until sprays have dried. Plan for the dog to spend the afternoon inside, and the beagle that digs to spend a little longer.
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Move what lives near the foundation
Pet bowls, toys, sandbox toys and garden tools along the walls go somewhere else for the day.
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Ask for the label and the safety data sheet
Any licensed applicator can give you both. The label is the legal instruction for how the product is used, and it answers most questions better than a forum can.
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Ask about indoor drilling
If they'll drill through a slab inside the garage or house, ask which rooms to keep closed, how they'll clean up, and when you can use those rooms again. Follow what they tell you.
About the cancer question
You'll find fipronil described as a "possible human carcinogen". That's the U.S. EPA's classification, and it's based on thyroid tumors in rats fed the highest doses in long-term studies. The National Pesticide Information Center notes there's no evidence it causes cancer in people.
That's not nothing, and it's one reason the label matters so much. The exposure the label is designed to prevent is contact with wet product or treated soil. Once the treatment is in the ground and dry, it binds tightly to soil and isn't expected to move into groundwater.
Termidor and the vegetable garden
This is the question I'd ask too. Termite treatments go in a narrow band right along the foundation. If your vegetable beds are against the house, ask the applicator before they start and follow what the label says for that site. The simplest fix for next season is moving edible plants away from the treated strip, which is good for termite prevention anyway (see does mulch attract termites).
Questions people ask
Is Termidor safe for dogs?
Once the treatment has dried, the risk to dogs is considered low. The label keeps pets out of treated areas until sprays dry, so keep dogs inside or away from the foundation on treatment day, and fill in any trenches so diggers can't reach wet soil.
How long after Termidor treatment can kids go outside?
The label says children shouldn't be allowed into treated areas until the sprays have dried. Ask your applicator how long that takes in your weather and soil, and keep play away from freshly dug trenches until they're filled in.
Is fipronil in Termidor the same as in flea treatments?
It's the same active ingredient. Some spot-on flea and tick products for pets contain fipronil, while Termidor is a termite concentrate that's diluted and put into soil. Never use one product for the other's job.
Can Termidor get into well water?
Fipronil binds tightly to soil and isn't expected to reach groundwater, but the label still forbids applying Termidor SC within 5 feet of a well or cistern. Point out every well before work starts.
Is Termidor safer than older termite treatments?
It's applied into the soil at a fraction of a percent, and it's one of the products that replaced chlordane, which was banned for termite use in the 1980s. How safe it is in your yard still depends on following the label, which is why only licensed applicators may use it.