Treating Work Clothes with Permethrin

Why this matters

Ticks get onto a tech at boot height and climb. Clothing treated with permethrin, a synthetic insecticide in the pyrethroid family, kills or disables a tick that crawls across the fabric, often before it reaches skin. CDC recommends it for people who work in tick habitat, and for a lawn, landscape, fence, pest or septic crew it is among the cheapest protective habits there is. It is also a pesticide, used on clothing by people who never read the label, around cats it can kill and drains that lead to streams. This card is how to do it correctly. Ticks themselves, the diseases and the check at the end of the day belong to Ticks and Tick-Borne Disease for Outdoor Crews and Doing a Tick Check and Removing a Tick Correctly.

Clothing treatment and skin repellent are two different products

Permethrin goes on fabric, never on skin. On skin it is broken down quickly and does little, and it can irritate. The skin side of tick protection is a separate EPA-registered repellent: DEET, picaridin, IR3535 or oil of lemon eucalyptus, applied to exposed skin per its own label. The two work together: treated clothing covering most of the body, repellent on the exposed wrists, neck and ankles. A crew that uses only one has a gap.

Factory-treated or home-treated

Factory-treated clothing has permethrin bonded into the fabric at the mill. It is labeled to last far more washes than home treatment, commonly dozens and up to about 70 on some labels, and nobody on the crew handles the pesticide. It costs more per garment and the choice of styles is narrower.

Home treatment uses a ready-to-use 0.5 percent permethrin spray or a soak kit labeled for clothing. A typical spray label states protection for about six washes or six weeks, whichever comes first; soak kits and other products state their own figure, and the label on the bottle in your hand is the one that counts. It is cheaper, works on the clothes the crew already owns, and needs to be repeated on a schedule someone has to keep.

Many shops split it: factory-treated socks and pants for the lower body, where ticks first make contact and where repeat treatment is easiest to forget, and home-treated shirts and hats.

The steps

1. Buy a product labeled for clothing, at 0.5 percent permethrin, with an EPA registration number. Read the label before you open it: what it may be applied to, how much, drying time, how many washes it lasts. Under the federal pesticide law, FIFRA, using any registered pesticide in a manner inconsistent with its label is a violation, and that reaches the person applying it. What breaks if you skip it: the mistake people make is buying a concentrated permethrin product sold for livestock, kennels or lawns and diluting it by guesswork for clothes. That is off-label use, the concentration is anyone's guess, and a concentrate is far more dangerous to handle and to cats.

2. Pick the outer layers that touch vegetation. Pants, socks, long-sleeved shirt, hat, boot uppers and gaiters. Do not treat underwear or anything not on the label, and never treat clothing while someone is wearing it. What breaks if you skip it: treating the shirt and forgetting the socks and pant cuffs leaves the exact path ticks use, from grass to ankle to waistband, unprotected.

3. Set up outdoors, away from cats, water and drains. Hang the clothes on a line or lay them flat on a tarp outside, on a calm day, with cats kept indoors and away. Choose a spot that does not drain toward a pond, a pool, a fish tank, a storm drain or a stream: permethrin is highly toxic to fish and aquatic insects, and runoff from a driveway reaches a storm drain fast. Wear nitrile gloves and stand upwind. What breaks if you skip it: spraying in a garage leaves you breathing the mist in a closed space, and spraying beside the storm drain sends it into the creek.

4. Spray evenly until the fabric is damp, both sides. Hold the nozzle about 6 to 8 inches from the fabric and move slowly, covering each garment front and back until it is visibly damp but not dripping. Spend extra on cuffs, sock tops, waistbands and collars, where ticks travel. Use the amount the label states per garment. What breaks if you skip it: a quick mist across the front of a pair of pants treats a third of the fabric, and ticks crawl up the untreated seam on the back.

5. Let it dry completely before anyone wears it or a cat touches it. Labels commonly call for at least two hours, and longer in humid weather; follow yours. Keep treated clothes out of reach of cats until dry. What breaks if you skip it: wet permethrin is the hazard to people and to cats. Dried into the fabric, it binds and transfers very little.

6. Write the treatment date on the garment. A laundry marker on the inside tag: date treated and a tally box for washes. What breaks if you skip it: a home treatment that lasts six washes is invisible once it is gone, so a crew wears expired protection for weeks believing they are covered.

7. Wash treated clothes separately, gently, and count. Wash them on their own, on a gentle cycle, and air or machine dry per the label. Dry cleaning strips the treatment, and long sun exposure breaks it down faster. Tick a box on the tag after each wash. Re-treat when the label's washes or weeks run out, whichever is first. What breaks if you skip it: washing treated work clothes with the family's laundry is the most common way permethrin ends up on clothing nobody meant to treat, including the kids' pajamas.

8. Pair it with skin repellent and a daily tick check. Treated clothing reduces bites; it does not end them. The end-of-day check still happens. What breaks if you skip it: the crew that treats its clothes and stops checking is the crew that finds an engorged tick on day three.

Cats, people and what to do if it goes wrong

Cats. Permethrin is highly toxic to cats, which cannot break it down the way dogs and people can. Most serious cat poisonings come from dog flea products containing concentrated permethrin applied to a cat. Treated clothing that has dried is a much lower risk, but keep cats off freshly treated clothes and out of the treatment area until everything is dry. A cat that shows tremors, twitching, drooling or seizures after contact needs a veterinarian immediately.

On skin or in eyes. If spray gets on your skin, wash it off with soap and water; it can cause a tingling or burning feeling that fades. If it gets in the eyes, flush with clean water for 15 minutes. For anything beyond that, or if someone swallows it, call Poison Control at 1-800-222-1222 with the label in hand.

A worked example

A lawn and landscape shop has four crew members working tick habitat from April through October, five days a week. Each person has three sets of work pants, shirts and socks, rotated so each set is worn once and washed every third workday.

With home spray rated for six washes or six weeks: each set gets washed once every 3 workdays, so it reaches six washes after 18 workdays. At five workdays a week, that is about 3.6 weeks, well before the six-week limit, so the washes run out first. Every set needs re-treating roughly every three and a half weeks. Over a 30-week season that is about 30 divided by 3.6, roughly eight treatment rounds of three sets per person, or around 24 garment-set treatments per person and nearly 100 for the crew. Somebody has to own that schedule, and in July nobody does.

With factory-treated pants and socks rated for 70 washes: each set washed every third workday reaches 70 washes after 210 workdays, which is 42 weeks at five days a week, longer than the 30-week season. The lower body is covered all season with no treatment rounds at all. The shop buys factory-treated pants and socks for the crew, which is where most first tick contact happens, and home-treats the shirts and hats every third Monday as a starting point. A three-week round lands inside the 3.6-week wash limit with a few days to spare; the monthly round the owner first proposed would have left each shirt unprotected for the last few days of every cycle, which is exactly the kind of gap nobody notices. The date and tally on each tag show when a set is due, and the shop trades roughly eight rounds of treating everything for about ten rounds (30 weeks divided by 3) of treating shirts and hats only, with nothing on the lower body left to expire.

What changes the answer: a crew that washes work clothes only once a week burns through washes far more slowly, so the six-week clock becomes the limit instead, and monthly home treatment of everything may be enough. A crew working brush and woods all day, rather than mowed turf, gets more value from factory-treated shirts as well.

The failure version: the shop sprays everything once in April with a bottle bought at a farm store, which turns out to be a concentrate meant for livestock pens, diluted "about right" in a garage, and nobody re-treats. By June the clothing has been washed two dozen times and protects nothing, and the crew is still telling customers they are treated.

How to tell it is working

• Every treated garment carries a date and a wash tally on the tag, and none is past its label limit.
• The product on the shelf is labeled for clothing, at 0.5 percent, with an EPA registration number.
• The tick log from the daily checks shows fewer attached ticks than the season before, not zero.

References

• CDC, Preventing tick bites: permethrin-treated clothing and EPA-registered skin repellents
• US EPA, Repellent-treated clothing and permethrin product registration and label directions
• Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), use consistent with labeling
• See related: Ticks and Tick-Borne Disease for Outdoor Crews
• See related: Doing a Tick Check and Removing a Tick Correctly