Coming Soon: Permethrin-Treated FRC for Bug Bite Protection

Tyndale Introduces Permethrin-Treated FRC

We’ve covered the dangers of using DEET-based insect repellent while wearing FR, and why you should apply permethrin to clothing instead. While FR clothing is considered the “last line of defense” in the event of an arc flash or flash fire incident, insect repellent is often the “first line of defense” against ticks and other blood-feeding, disease-carrying insects.

A big concern for outdoor workers are ticks; deer tick nymphs are the ones responsible for transmitting Lyme disease. Basically, nymphs are engorged larvae that molt over winter and emerge in May. In fact, most cases of Lyme disease are transmitted from May through July (1). These ticks are often hidden in leaf litter, and mostly latch on to shoes or socks, and then climb up your leg (2).

Permethrin Insect Repellent

Insect repellent for FR clothing is specifically formulated to provide protection against biting insects without reducing the safety benefits and protection of FR clothing. Insect repellent like permethrin prevents the spread of Lyme disease and West Nile Virus, among other infectious diseases caused by insects.

Quick facts about permethrin:

  • Permethrin is over 2,250 times more toxic to ticks than humans.
  • DEET, the active ingredient in most insect repellents, can be absorbed at 20x the rate of permethrin (which although not typically applied to skin, will absorb less than 1% of the active ingredient).
  • A 140-pound person would have no adverse health effects if exposed to 32 grams of permethrin/day. However, there is less than 1 gram of permethrin in an entire bottle of clothing treatment (3).

The main difference between permethrin and other types of insect repellents, like DEET, is that permethrin is applied directly onto clothing rather than your skin. According to, this method has many benefits over ordinary insect repellent:

  • Chemicals are not applied directly to the skin, which may help reduce chemical exposure and increase the duration of efficacy; and
  • Permethrin-treated clothing will last through multiple launderings, reducing the number of reapplications (4).

Pre-Treated FRC

A study, conducted by The University of Rhode Island, found that permethrin-treated shoes and socks provided 74x protection from ticks latching onto shoes and crawling up legs. Only one test volunteer received a tick bite among all test subjects wearing permethrin-treated shoes and socks compared to 27% of volunteers that received tick bites while wearing untreated socks and shoes. In fact, regardless of the permethrin application method, test subjects wearing outfits treated with permethrin received over 3x fewer tick bites than test subjects wearing untreated clothing (4).

Tyndale proudly adds to our selection of FRC, products that will come pre-treated with this FR-safe insect repellent. Tyndale’s FRMC® fabric supplier, Front Line Fabrics (FLF), will begin applying Perimeter Insect Guard, a permethrin treatment, to Tyndale’s F920T socks. As the University of Rhode Island study demonstrates, socks pre-treated with permethrin are an effective first step to keeping ticks from biting you.

Additional Resources offers a variety of informational resources to educate yourself and your workers on ticks and the risks of working outside. Their resources include videos, seasonal information on tick dangers and the spread of viruses, as well as prevention tips.

Stay tuned for permethrin-treated FRC available from Tyndale or Contact Us at 800-356-3433 to be included in Tyndale’s upcoming permethrin-treated socks wear trial!


References for this post were accessed August 2014:





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