Pesticides are used to stop insects and other pests from ruining fruits and vegetables, but they can also harm people and the environment.

Intensive agriculture has made pesticides part of our food chain, so they are unavoidable, but there are limits in place and they are monitored by the U.S. Environmental Protection Agency, who make sure that pesticides used on foods meet strict standards.

The EPA sets limits for the amount of pesticide residue that can remain on foods, and it determines the limits by looking at a number of factors. These include the pesticide’s level of toxicity, how much and how often it is used, as well as how much of the food an average person is likely to eat.

There are legal residue limits, and the EPA has to make a safety finding the pesticide can be used with “reasonable certainty of no harm.” This applies to food grown in the U.S., as well as imports.

The U.S. Department of Agriculture keeps a database of pesticide residue in foods. In 2015, 85 percent of 10,000 pesticide samples had “detectable” pesticide residue, but less than 1 percent of samples had residues that exceeded the limits set by the EPA.

The EPA website says that “just because a pesticide residue is detected on a fruit or vegetable, that does not mean it is unsafe. USDA’s Pesticide Data Program (PDP) detects residues at levels far lower than those that are considered health risks.”

What Are the Actual Dangers?

Pesticides are made to kill living organisms, so it’s not surprising that they can cause health risks in humans in some cases. These risks depend on the toxicity of a pesticide’s ingredients, but also on how much you are exposed to them.

Some groups of people, such as children, pregnant women, sick people, and the elderly may be more sensitive to pesticides than others, says the National Pesticide Information Center, which is a project of Oregon State University and the EPA.

A lot of scientific studies look at those who come in direct contact with pesticides because they work with them, or are exposed to them in their homes, work, or schools. Consuming small amounts of pesticides in food may be concerning, but studies don’t often show the difference between direct contact with pesticides, limited exposure, and ingestion.

There have been several studies that have looked at the link between pesticides and health issues:

1. Cancer

There have been many studies that have investigated links between pesticides and certain types of cancer. Some links have been found between exposure and childhood leukemia, brain cancer and lymphoma, as well as breast cancer. There have also been studies on pesticides and prostate, pancreatic, and liver cancers, as well as the increased risk of melanoma.

2. Neurodevelopmental Issues

Pesticide exposure in pregnant women and in children has been investigated as a possible source of neurodevelopmental delays, impaired motor skills and behavioral problems.

3. Disrupted Hormones

Some chemicals in pesticides can disrupt hormones like estrogens, thyroid, and androgens, which could have an impact on reproduction.

4. Neurological Issues

Studies have shown that farmers exposed to some pesticides have a 70 percent higher risk of developing Parkinson’s disease.

5. Skin, Eye and Lung Problems

Like many other chemicals, pesticides can result in irritation for some people, depending on how much they are exposed to them.

How to Reduce the Dangers

Each year, the Environmental Working Group produces the Dirty Dozen – a list of conventionally farmed fruits and veggies found to have the highest levels of pesticide residues.

Strawberries came top of the list, and nearly all samples of strawberries, spinach, peaches, nectarines, cherries, and apples tested positive for pesticide residue.

EWG recommends that people buy organically grown versions of these foods whenever possible, to minimize the risks. However, research in 2011 says that eating organic produce doesn’t mean you’ll avoid pesticides – 23 percent of organic food samples tested positive for pesticide residues.

The best solution is to wash your fruit and veggies under running tap water, and use a vegetable brush to scrub away a residue. That may not help with waxy, or soft skinned fruits, says the National Pesticide Information Center. If the produce has been treated with wax, the residue may be sealed underneath the wax.

You can buy fruit and vegetable washes, but they haven’t proven to be any more effective than water, and the detergent residue can stick to your produce instead.