Permethrin: The Facts
Permethrin has been used as a pesticide since 1977. At that time it was regulated only for use on cotton plants and in head lice ointments. Today, permethrin is also used as a pesticide on a variety of different products, including fruit, meat, and vegetables.
Common Questions Answered
Here are some straightforward answers to the common questions regarding permethrin:
What is Permethrin? Permethrin is a synthetic product that was approved in 1977 by the Federal Department of Agriculture as an insecticide. However, since that time, head lice resistance to permethrin has become widespread. Certain popular head lice lotions that use permethrin are promoted, as long as they are used in a geographical area that is not already resistant to permethrin.
What is Permethrin Used For? Permethrin is used in a variety of insecticides, including several head lice lotions and bug sprays. Approximately two million pounds of permethrin are used annually, with about 70 percent being distributed in non-agricultural places. 55 percent of that is used by professionals, 41 percent by homeowners, and four percent is applied on mosquito abatement areas.
Are Any Insects Immune to Permethrin? A variety of insects show immunity to permethrin. Among those insects are the head louse, the house fly and the army worm. Unfortunately, at the same time, some insects that are beneficial to humans are not immune to this pesticide, including the all important honeybee.
What are the Effects of Permethrin Toxicity? Because permethrin affects the nerves, it has the potential to cause neurological damage in sensitive individuals. After the Environmental Protection Agency (EPA) evaluated the toxicology and ecological effects of this chemical, it was determined to be a weak carcinogen, though highly toxic to fish and aquatic invertebrates. While there is some concern over tumors grown in lab mice and how permethrin might affect humans, the EPA determined the risks did not reach a high enough level of concern. Children are more susceptible to permethrin toxicity than adults. Early experiments discovered that permethrin can target the immune system and cause a variety of illnesses, some of which may occur in the reproductive organs and cause damage to the unborn fetus. Additionally, permethrin is a mutagen, and capable of causing chromosome abnormalities. Potential damage to a breastfeeding infant is not known at this time.
Is Permethrin a Carcinogen? Yes. But the EPA has determined permethrin to be a weak carcinogen, and classified it as a Pregnancy B Drug. Pregnancy B Drugs are drugs that show little or no evidence of risk to humans. However, because permethrin is a carcinogen, even a weak one, there still is a chance that a fetus could be harmed by this chemical. Additionally, it is unknown whether it is safe for use during breastfeeding.
Why is Permethrin Still in Use? Because of its low cost and high efficiency, permethrin is the most widely used mosquito repellent in the United States. Unfortunately, while permethrin is considered a carcinogen,highly toxic to fish and other aquatic vertebrates, and a cancer and reproductive risk, the EPA has decided the health risks to humans fall below their level of concern.