A white cloud of pesticides had drifted into Fidelia Morales’s back yard, coating her children’s swing set.

The 40-year-old mother of five gestured toward the citrus groves that surround her house in California’s Central Valley as she recounted when an air blast sprayer sent chemicals floating onto her property last year – landing on her family’s red and blue jungle gym.

“We know this is dangerous for the kids, but what are we supposed to do?” she said on a recent afternoon, speaking in Spanish through a translator. Morales said she fears that these kinds of drifts, as well as long-term exposure to a variety of chemicals in the air, have hurt her children, ages 9 to 20, who have struggled to focus in school and have suffered from bronchitis, asthma and other chronic illnesses.

Under Barack Obama, the US Environmental Protection Agency (EPA) proposed an agricultural ban on chlorpyrifos, one pesticide widely used in her region, based on the growing body of research documenting the risks for farm workers and communities, including links to brain damage in children.

Donald Trump’s administration, however, has rejected the science, announcing a reversal of the ban. That means that despite recent victories for families and environmentalists who have fought for more than a decade for protections from the insecticide, widespread use will continue in California, where a majority of the fruits and nuts in the US are grown.

“There’s a sense of helplessness,” said Luis Medellin, a 30-year-old dairy worker, sitting with his three younger sisters at his family’s home in the small agricultural town of Lindsay. “I’m being poisoned and I can’t do anything about it. It’s like a slow death.”

More than a dozen Latino residents in Tulare County, a rural farming community three hours north of Los Angeles, shared stories with the Guardian of direct pesticide poisonings from drifts and the long-term health challenges that they believe are linked to chronic exposure. They described children vomiting, suffering painful skin irritations, debilitating headaches and dizziness, as well as developing autism, learning problems, attention deficit disorders and respiratory ailments.

It’s difficult to conclusively determine how chlorpyrifos may have contributed to individual children’s conditions, but epidemiological studies have found links between the pesticide and a number of health conditions – research that led EPA officials to recommend the ban in 2015. Manufacturers and growers continue to assert that the chemical is safe and say that the studies are flawed.