Six pesticides play an oversized role in undermining the safety of the fruits and vegetables Americans regularly consume. These pesticides contribute the most risk in the lowest-rated fruits and vegetables in CR's study.

In some cases, a pesticide appeared in almost all of the samples of a particular fruit or vegetable. In other cases, a pesticide was detected in only a small percentage, but at worrisome levels.

More about the pesticides on produce

And that's a problem, because it's impossible for a consumer to know if the specific fruit or vegetable they choose in a store is one that's contaminated or not.

If growers replaced these pesticides with more sustainable pest-management methods, many fruits and vegetables would be much safer. That's why CR urges growers to stop using these chemicals and the Environmental Protection Agency to ban them.

Acephate

This pesticide can break down into a chemical called methamidophos, a compound banned as a pesticide in the U.S. since 2009 because it's a neurotoxin, meaning it damages the brain and nervous system. Acephate use is probably the reason methamidophos is still found on produce. It contributed the largest share of the risk for fresh green beans and was found in troubling amounts in about 10 percent of the samples. It's also responsible for a majority of the risk in nonorganic and U.S.-grown frozen or canned green beans, summer squash, celery, and imported mangoes and watermelon.

Chlorpropham

Used to keep potatoes from sprouting, this pesticide is banned in the European Union because it may interfere with hormones in the body, especially thyroid hormones. It was found in concerning amounts on nearly every sample of nonorganic U.S.-grown potatoes and 96 percent of imported ones. It was even found on every sample of organic U.S.-grown potatoes, though at much lower levels. While the pesticide isn't allowed on organic produce, it may end up on organic potatoes when processing plants or storage bins aren't thoroughly cleaned between batches.

Chlorpyrifos

The EPA was on the brink of banning this neurotoxin in 2016 but reversed course in 2017 after intense lobbying from the pesticide industry, saying more research was needed. It contributes significantly to the risk in nonorganic peaches. Seventeen percent of imported samples and 2 percent of U.S.-grown samples had worrisome levels of chlorpyrifos. But it sometimes shows up at lower levels on organically grown produce too, including broccoli and grapes.

Cyhalothrin

It's thought to interfere with the body's neuromuscular system. It's the major contributor to the risk in cherries and was found in more than half of nonorganic U.S.-grown samples, fresh and frozen. It's also responsible for some of the risk in other types of produce, including nonorganic U.S.-grown kale, lettuce, nectarines, tomatoes, and spinach, and imported lettuce, snap peas, tomatoes, and frozen green beans.

Famoxadone

Some research suggests that this pesticide is a hormone disruptor. CR thinks it shouldn't be used on food until more is known about its safety. It's the main reason both nonorganic and U.S.-grown organic spinach fare poorly in our ratings.

Fludioxonil

This is one of several risky fungicides that's used after harvest, and it's thought to have hormone-disrupting effects. Of this group, fludioxonil was the one that contributed the most risk in our analysis. It's primarily responsible for the high risk in nonorganic fresh peaches and nectarines. It was found in 90 percent of U.S.-grown nectarines, 78 percent of U.S.-grown peaches, and about half of imported versions of both. It's also a factor in the risk for nonorganic apples, applesauce, cherries, kiwifruit, pears, plums, and potatoes.

What About Glyphosate and Dicamba?

These two commonly used headline-making pesticides weren't part of our analysis. That's not because they're risk-free, but because they're mostly used for growing grains and beans, not fruits and vegetables.

Glyphosate, the active ingredient in Roundup, is sometimes used in home gardens, and both chemicals are used on corn and soybean plants that have been genetically engineered to be resistant to them. Glyphosate and dicamba destroy weeds but leave the plants unharmed. (Glyphosate can also be found on other crops, including oats and chickpeas.)

The World Health Organization's International Agency for Research on Cancer classifies glyphosate as a probable cancer-causing agent, and dicamba is known for drifting from where it's applied to neighboring farms, killing those crops. That's why a U.S. Court of Appeals ruled earlier this year that the Environmental Protection Agency shouldn't have approved dicamba in the first place.

CR's safety experts believe these two pesticides should also be prohibited.

Editor's Note: This article also appeared in the October 2020 issue of Consumer Reports magazine.

This article has been updated to clarify that the World Health Organization's International Agency for Research on Cancer, rather than the World Health Organization as a whole, classifies glyphosate as a probable cancer-causing agent.