A pesticide chemical once slated to be banned by the EPA is likely responsible for the sudden illness of a group of farm workers near Bakersfield, California.

On May 5, pesticides drifted over to workers harvesting cabbage from a nearby mandarin field. According to local reports, 12 people reported vomiting, nausea, and one person fainted.

A representative from Kern County Department of Public Health issued a statement asking anyone exposed to the pesticide to seek medical attention immediately. “Don’t wait. Particularly if you’re suffering from any symptoms. Whether it’s nausea, vomiting, diarrhea, seek medical attention immediately,” said Michelle Corson.

The pesticide contained a chemical called chlorpyrifos, which is widely known to be highly toxic. According to Mother Jones, whether chlorpyrifos was responsible for the workers’ symptoms is still under investigation, but the Kern County Department of Public Health assumes it was the active ingredient.

Chlorpyrifos is used in pesticides applied to over 50 crops in the United States, including soybeans, peaches, corn, strawberries, broccoli, apples, onions, and asparagus. In other words, it’s very common.

A 2016 EPA report on chlorpyrifos details how exposure to the chemical is linked to an “increased risk of delays in mental development, intelligence loss, attention problems and autism spectrum disorder in children.” Its toxicity can be harmful to anyone if it’s touched, inhaled, or eaten, and can bring on muscle twitching, lack of coordination, weakness or tremors, cramps, and blurred or darkened vision.

The EPA was on its way to banning chlorpyrifos before the current administration took over. In October 2015, they announced that the residue of chlorpyrifos left on food crops exceeded safety standards set by the Federal Food, Drug, and Cosmetic Act, and in 2016 they went even further to include its harm to drinking water:

“The majority of estimated drinking water exposures from currently registered uses, including water exposures from non-food uses, continue to exceed safe levels even taking into account more refined drinking water exposures.”

But the Trump administration pulled an about-face at the end of March, when EPA Chief Scott Pruitt signed an order denying a petition to ban the chemical’s use on agriculture, citing a lack of reliable data on chlorpyrifos’s harm.

“We need to provide regulatory certainty to the thousands of American farms that rely on chlorpyrifos, while still protecting human health and the environment,” said EPA Administrator Pruitt. “By reversing the previous Administration’s steps to ban one of the most widely used pesticides in the world, we are returning to using sound science in decision-making – rather than predetermined results.”

Chlorpyrifos’s parent company, Dow Chemical, released a statement supporting Pruitt’s decision. With the EPA’s recent decision to fire scientists in order to make room for industry on its review boards, Pruitt’s decision on chlorpyrifos could be the beginning of a trend.

Photos via Getty Images / David McNew