The threat of the Zika Virus grows every day, and the need for clear information is especially pressing if you are pregnant. How do you prevent getting infected with the Zika Virus, and what insect repellents are best? The first question is easy to answer: public health experts agree that women who are pregnant or who might be pregnant should use insect repellents. The answer to the second question is not so simple.

I am a former senior official at the U.S. Environmental Protection Agency (EPA), and familiar with how the U.S. evaluates and approves pesticides, which include insect repellents. It is not easy for the average consumer to know what works and what does not work. Unfortunately, EPA policies have made this question much more complicated, having made important distinctions between some “natural”-type repellents and other products available in the marketplace.

Years ago, EPA de-regulated a number of natural, non-toxic materials from being subject to the registration requirements of the federal pesticide law (the Federal Insecticide, Fungicide, and Rodenticide Act). This made sense at the time since garlic, pepper, rotten eggs, vinegar, and other common chemicals are sometimes used as pesticides. Before de-regulation, these products were also subject to the same requirements as synthetic chemical pesticides with long unpronounceable names (e.g., diethyltoluamide, better known as DEET) which EPA requires to have volumes of efficacy and safety test data. Being natural does not mean a substance is non-toxic; some natural ingredients are fully evaluated and widely used. But in the interest of efficient use of resources EPA issued a list of products that could be sold as pesticides, but would not be subject to EPA data requirements and review (EPA calls them “minimum risk pesticides”).

This list of pesticides which are not subject to EPA evaluation, and which are not required to have data which proves they are effective, includes a number of botanical ingredients, such as oil of citronella, geranium, rosemary, peppermint, and many others. Many of these products can be used as pesticides -- some may work better than others -- and many work for the intended use (example: rotten eggs, or as EPA refers to them -- “putrescent whole egg solids” -- are used as a deer repellent).

Many of these ingredients have been marketed as “natural” insect repellents, and labeled as “safe” or “non-toxic” using words that will not appear on products where EPA reviews and approves the instructions on the product label.

Here is the bureaucratic distinction which matters greatly to EPA, but will not be understood by consumers:

  • If the repellant label includes “public health claims” -- that it repels mosquitoes that may cause a disease (like Zika Virus or West Nile Virus) -- then the product has to have data showing that it works;
  • If the product just says “repels mosquitoes,” it is not required to have data that shows it is effective, and may very well be ineffective.

Few, if any, humans outside of EPA label experts realize this important distinction: if there is no health claim on the label, then it is, in effect, a situation of “buyer beware.”

What remains: EPA’s deregulation of these products means it is legal to sell products which do not work, as long as the ingredients appear on the EPA minimum risk pesticides list.

Consumer Reports (CR) recently reported in May of this year on studies conducted on repellents. Their results:

  • Using a “natural” mosquito repellent, with active ingredients such as citronella or clove, lemongrass, or rosemary oils, might seem like a good idea, especially if you’re pregnant or planning to be.
  • But five of the six plant-based repellents we tested…lasted one hour or less against Aedes mosquitoes, the kind that can spread Zika.

Not all repellents with the same ingredient are equally effective, and they found that some formulations of the chemical repellents also do not work for very long in their tests. Some botanical pesticides are effective and have the public health claims on the label (example: lemon eucalyptus, a botanical ingredient not on the exempt product list, and CR testing did find it to be effective).

To reduce confusion about what works, EPA for years has struggled to correct the situation by trying to impose changes to the requirements for insect repellents.

Unfortunately, to end the confusion about the difference between “repels mosquitoes” and “repels mosquitoes that can cause the Zika Virus,” EPA has to conduct a rulemaking which requires a long and bureaucratic process to complete. The good news is that EPA is working on such a solution. The bad news is that they have been working on it for almost ten years and they still have more work to do. There are details and petitions and proposals and reasons why it has taken so long, but it is the kind of story that gives bureaucracy a bad name.

With the onset and fears about the Zika Virus, however, EPA should make the needed changes immediately to ensure that consumers are not misled into using products which are not proven effective in repelling mosquitoes.

From a consumer’s point of view, it really is that simple. Legally, it is more complicated. In the meantime, EPA should be loud and clear in its communication about the distinction, even if they cannot take immediate action to reduce the confusion.