When most of us think of pesticides, we generally think of crops. However, pesticides can end up in our homes and bodies in ways beyond just food. Products like over-the-counter lice treatments, pet shampoos, gardening products, and bug sprays can all contain registered pesticides too. This blog contains information about two pesticides – permethrin and pyrethrins – how they can find their way into your home and ways you can minimize your exposure.
Remember that every single decision you make to reduce your exposure to potentially harmful substances is important and a step in the right direction. Toxic-free living isn’t a destination – it’s a journey. And that journey is comprised of small, but meaningful – and very powerful – decisions.
What Are They?
Permethrin is a pesticide most frequently used to treat bug-resistant clothing, mosquito netting and outdoor gear, though it’s also often used in bug sprays and very commonly used worldwide as a pesticide for crops. In addition to these uses, permethrin is used in over-the-counter lice treatments, as well as in flea shampoos and treatments for pets.
Though it’s a little more complicated than this, you can think of pyrethrins as the natural counterpart to permethrin. Pyrethrins are a mix of six chemicals found naturally in chrysanthemum flowers. They are typically extracted from the flower, but sometimes the whole, crushed flower is used, which is called pyrethrum powder. Pyrethrins are used in products meant to control bugs like household insecticides, foggers, sprays, dusts, and pet shampoos. Pyrethrins are also used on crops. They are also used in over-the-counter lice treatments, as well as flea shampoos and treatments for pets.
The Health Concern
Permethrin is a neurotoxin which acts on sodium ion channels, promoting repeated nerve impulses. When permethrin is found at high levels, it can affect the function of chloride channels, which may result in seizures. One study found that permethrin and DEET, either in combination or separately, were linked to the death of neural cells in various parts of the brain, which may lead to physiological and behavioral issues, including problems with motor skills, learning and memory. Another study found that newborn exposure to permethrin impaired working memory by interfering with neural processing in the frontal lobe of the brain.
Orally, permethrin is considered a likely carcinogen by the EPA. More research is needed on carcinogenicity when exposed through the skin. Permethrin is toxic to fish, aquatic life, and bees.
Just because pyrethrins are natural does not mean they are inherently safe. Pyrethrins have been linked to endocrine disrupting effects through limited research; more study is needed. Pyrethrins may also be associated with the development of allergic sensitization, and if you are allergic to ragweed, exposure can cause difficulty breathing or an asthmatic attack.
In multiple cases, people’s exposure to pyrethrins and pyrethroids (the class of pesticides to which pyrethrins belong) through in-home use products like flea shampoos for pets to has led to death. Pyrethrins are also toxic to aquatic life and bees.
How to Avoid It
- Seek out nontoxic lice treatment and prevention products, as opposed to conventional over-the-counter products. Read our guide to learn how to choose safer options – Lice: Treatment & Prevention.
- When it’s time to give the dog a bath, use good old-fashioned shampoo, soap and water. Or try a gentle all-purpose castile soap. There is no need to use flea shampoos when you’re not experiencing an infestation.
- If you need flea prevention or treatment, look for natural options as opposed to those containing pesticides. Some companies make pet-safe herbal shampoos intended to prevent fleas. You can even DIY your own flea sprays using pet-safe essential oils, but make sure to consult your vet about essential oil safety for your pet.
- Choose alternative and safer bug repellent options. For tips on choosing safer bug repellent and control, check out our fact sheet and report.
- Use a welcome mat and take your shoes off when you enter your home. Pesticide residue can be tracked into the home through shoes worn outside.
- Wash all fruits and vegetables thoroughly, including organic produce. Look for pesticide-free produce when possible. (Tip: check out the farmers’ market and ask what they use. Farmers love talking about their food!)
- If you’re a gardener, give natural and organic methods a try to reduce your exposure to pesticides. Visit your local natural greenhouse for tips. There are numerous books and online guides available too.