Using Borax to Kill Fleas – The Dangers Not Many Homeowners Know

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Borax is a popular option for pest control. But there’s more to this method than just throwing powder into your carpet and leaving it there overnight. Using borax to kill fleas has certain precautionary steps, disadvantages and even dangers that you have to know before you consider it.

Using Borax to Kill Fleas – The Dangers Not Many Homeowners Know

Fleas die when they make direct contact with borax. CC Image courtesy of the NY State IPM Program at Cornell University and Frédéric BISSON on Flickr

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Are borax and boric acid the same?

Fundamentally, boric acid and borax are different. In their chemical forms, borax is a kind of salt called sodium borate while boric acid is hydrogen borate. They also come from different substances. Borax is mined and refined from kernite, colemanite and tourmaline while boric acid is taken from sassolite.

Nevertheless, because these two materials give out roughly the same effects in a lot of the products that they’re mixed into, their names have become interchangeable for many homeowners and for people who dabble in pest control.

Both substances also have a nasty reputation for causing health problems on their users. Boric acid, in particular, is officially listed by the Occupational Safety and Health Administration Hazard Communication Standard as a hazardous material. That’s because, at a substantial amount, the powder can cause health problems for both humans and pets.

Here in FightBugs, we use boric acid and borax interchangeably since they don’t have any huge difference between them and they give out same effects when used on pests.

Dangers and Disadvantages of Using Borax

If you’ve set your sights on using borax to kill fleas, hold on for a moment. Take a few minutes to read the dangers and disadvantages first. It’s best to know what you’re heading into before you apply this treatment.

Here are only some of the known issues borax causes when it’s sprinkled into a home.

  • Borax can be a short-term irritant on the skin. It causes itching and rashes.
  • It can also irritate your eyes giving you mild burning and redness.
  • Pets and borax don’t mix. In fact, inhaling the powder can cause long term lung problems for cats.
  • According to the Environmental Working Group, chronic exposure to the powder can cause dogs to develop testicular atrophy.
  • More than 5 mg of borax is dangerous when ingested. This can cause cardiovascular problems and other health issues for pets.
  • The powder can also induce vomiting, nausea and oral irritation to humans.
  • Toddlers and babies face the risk of hand-to-mouth transfer when borax treatments are applied in the house.
  • Pregnant women can also develop problems when they’re near borax. So if you’re expecting, use another natural treatment instead.
  • This substance can harm men’s reproductive system, making them susceptible to decrease sperm count and libido.
  • Borax can also damage carpet fibers if they’re wet during the treatment.
  • Finally, the powder can kill plants. Its particles enter plants and suck the moisture out of them, just like how it would kill insects.

How to Safely Use Borax to Kill Fleas


But if your decision to use borax is set in stone or if there are no other options to take, consider these safety steps or precautions when using the powder.

  • Always wear a mask. Even if borax isn’t overly toxic, inhaling a substantial amount of it can still damage your lungs.​
  • Open the windows. Since breathing in the powder is dangerous, let the air in. Only close the windows when you’re about the leave the room you’ve just treated.
  • Wear gloves. Treat borax like any other hazardous chemical. Wear gloves so that it can stop the powder from irritating the skin on your hands.
  • Wear pants and long sleeves. Basically, you shouldn’t let any part of your body be exposed.
  • Cut off all access to that corner of the house. Don’t take any chances. Don’t let your pets and your kids anywhere near the borax-filled area. If it’s a room, lock the door shut and use door seal sets to keep the fleas from escaping under the door.

So even though using borax to kill fleas seems like a good idea, the powder is actually quite toxic when the right amount of it unluckily hits a victim. What we should do instead is to find other natural treatments before resorting into the use of boric acid or any kind of toxic material for that matter.

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