Permethrin And The DOD Chemical Protection System:
The Department of Defense (DoD) utilizes a system of two chemical components in conjunction with the field dress uniform. The EPA approved components of this system include the insecticide permethrin and the insect repellent deet (N, N-diethyl-m-toluamide) in concentrations less than 33%.
Note: Not all permethrin is blended for the purpose of bonding to the fabric. Most permethrin is agricultural which is for pest control on vegetation. Its design purpose is to stick to plants thus protecting the plants. Veterinary products are designed to adhere to animal skins/hair or premises and are not for fabric application. Some permethrin is formulated for treatment of medical conditions such as head lice and scabies. The formulations are not interchangeable mostly because of solvents utilized. Always refer to manufacturers label and follow instructions.
Permethrin is virtually non-toxic to humans and no systemic effects have been reported. In EPA and FDA tests, it was uncommon to have any skin reddening, rash or other irritation. When used as a repellent, permethrin is applied to exterior clothing where it dries and bonds to the cloth fiber. This water-based formula is non-staining, odorless and has exceptional resistance to degradation by sunlight (UV), heat and water. Although permethrin is approved for skin application under certain circumstances such as head lice formulas, it is not applied to skin as a repellent. Permethrin does not bond to skin (stick) and is quickly deactivated by skin’s esterase action into inactive compounds. Because of these attributes permethrin offers no repellent benefit on skin. It is only effective when used as a clothing treatment. Deactivation of permethrin on skin occurs in approximately 20 minutes, When placed on clothing it will last 2 to 6 weeks (even up to 1 year with special application) and will last through weekly launderings. With the long history of success permethrin has achieved, it is best not to second guess these extraordinary results. By following the directions provided on the product you can be assured of results that achieve protection at or near 100%. Any variation of instructions that indicate using less permethrin on clothing will result in diminished performance. Follow the direction exactly and you will be amazed at the performance of this product.
Permethrin Mosquito Tests: The early history of permethrin development involved tests on mosquitoes conducted by the US Army and Air Force. Tests showed that when lightweight uniforms were treated until moist (approximately 3 ounces) the permethrin alone (0. 5% solution) gave 97.7% protection from mosquitoes and 99.9% protection when used in combination with deet (33% solution). Two detergent washings did not diminish mosquito repellent and killing action of permethrin-treated uniforms.
An interesting side note: The effectiveness of permethrin can be shown in the following report highlight that was reported in a very matter of fact statement. During testing in the Everglades, “Mosquitoes were also repelled because of the side-stream effect caused by numerous treated uniforms within the same general location. This required that the test site be moved to locate more mosquitoes!” Now that’s performance . . .
Permethrin Tick Tests: Test on ticks conducted in Massachusetts concluded that 100% protection was provided against the Deer tick (Ixodes Scapularis) which is the primary vector of Lyme disease in the Midwest and Northeast. The same outstanding results occurred when testing the Western Black Legged tick, Lone Star tick, American Dog tick and Brown Dog tick. Similar results have been found with other tick species throughout the United States and Europe. Two detergent washings did not diminish repellent killing action of permethrin-treated uniforms. In tests, ticks that crossed only 10 inches of treated fabric fell from the uniform, later died due to this limited exposure.
Note: Military application of permethrin (Permethrin Arthropod Repellent) varies from the civilian application in that 4.5 ounces are applied to the uniform and the remaining contents of the 6-ounce container used to treat mosquito netting. The difference in the application also results in increased protection. It is specified that “reapply after six weeks and sixth laundering.” The additional 1.5 ounces doubled the 2 to 3-week protection realized from the civilian application of 3 ounces. Full protection is realized by use of permethrin AND application of standard-issue repellent approved for skin application (3M Ultrathon)
DEET (N, N-.diethyl-m-toluamide): is an approved repellent for skin application. Exposure to high concentrations of deet can pose some limited health hazards. At the time concentrations of 33% as provided in the 3M Ultrathon product were chosen by the U.S. Military for its superior performance and high margin of safety. Up until the 3M Ultrathon was chosen the military had been using a 100% deet. It was uncomfortable to wear and easily damaged certain materials synthetic and plastics. Since the 3M Ultrathon introduction, some new developments have been made using deet in special microencapsulated formulas that have tested quite well and last up to 20 hours between applications against certain insect species. Deet-based products are available in a wide variety of formulas that can address the very specific needs of the individual traveler, outdoors person, family member, and even young children.
Early research on deet showed that performance dropped off when concentrations of 35% or higher were tested. As an example, if a 30% deet concentration offers satisfactory repellent action for four hours, an assumption that a 60% deet would last eight hours is not correct. The 60% product may only last about 5 hours. In the use of standard deet formulas, it is more effective to use lower concentrations of deet with more frequent application than to assume the higher concentrations to be longer lasting. They are not. Most brand-name deet-based products already have a deet range from 15% to 33%. Once the threat of insect/tick bite is over, the repellent should be washed off. Deet by itself tested between 85% to 89% effective at repelling ticks (deet does not kill either ticks or mosquitoes) and 97% against mosquitoes.
The DoD system consists of both permethrin-treated clothing and deet applied to the exposed skin. The use of one without the other will undermine the system and increase the risk of insect or tick bite. Many non–deet products are available on the market and are not part of the DoD protection system. They show ineffective repellent performance and are not recommended for any situation where disease transmission is a threat.