New York’s two U.S. senators are pressuring federal environmental officials to speed up a health study examining the risks from exposure to 1,4-dioxane — a man-made chemical and possible carcinogen found throughout Long Island’s drinking water supplies.

On Thursday, Sens. Chuck Schumer and Kirsten Gillibrand, both Democrats, sent a letter to acting Environmental Protection Agency Administrator Catherine McCabe, asking for faster efforts to evaluate the health risks and to provide assistance to affected Long Island communities.

Newsday earlier this month reported that 1,4-dioxane had been found in 71 percent of water districts sampled on Long Island at a level that poses a one-in-a-million cancer risk after prolonged exposure.

Nationwide, the same risk was reported in only 7 percent of water supplies tested as part of an EPA-mandated survey that covered all large water suppliers and a sampling of smaller suppliers.

“State officials and water districts are struggling to coordinate the best course of action and are in need of more data, analysis and direction from the EPA,” the senators wrote to McCabe, who was the agency’s deputy regional administrator in New York City under former President Barack Obama.

EPA representatives did not respond to a request for comment Thursday.

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The chemical, which often is used as a stabilizer for manufacturing solvents, also is present in personal care products such as sunscreen, acne cream and deodorant.

The agency has not set a safe drinking water standard for 1,4-dioxane, so it is considered unregulated. And there is no approved removal method in New York State, though a pilot system to treat for the contaminant will begin operation in April at a Suffolk County Water Authority well.

Late last year, the EPA named 1,4-dioxane as one of 10 chemicals that it planned to do health risk assessments for under the Toxic Substances Control Act, or TSCA.

By June 19, the EPA must document how the chemicals are used, exposure paths, hazards and populations that could be most susceptible to health risks. Within three years — not including a possible one-time six-month extension — a final chemical risk evaluation must be completed.

Schumer and Gillibrand want the assessment to be completed in a more timely manner.

“Long Island homeowners cannot afford an EPA rain check when it comes to investigating 1,4-dioxane and its impact on our local water,” Schumer said in a news release.

Under TSCA, which was amended in 2016, the EPA is required to act quickly when water supplies are at risk, Gillibrand said.

“It’s unacceptable that while the drinking water on Long Island is contaminated with a possible carcinogen, the EPA is not acting with the urgency that the situation requires in order to clean up our water supply,” she said in a news release.

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It’s unclear whether a freeze on hiring, new regulations or outside contracting placed on some federal agencies by President Donald Trump would affect the timeline of the health risk assessment.

The EPA did not respond to a question Thursday about the new administration’s effect on the timing of the assessment.

New York State Sen. Todd Kaminsky (D-Long Beach) said he still would push for a bill he sponsored this month that would require the state Department of Health to assess the risks of 1,4-dioxane.

“We all should be pushing, but I see no evidence thus far that we could be absolutely certain EPA will do this,” Kaminsky said of speeding up the federal agency’s review. “We want the EPA to weigh in on this, but we certainly can’t wait on it.”

In a statement, a spokesman for the state Health Department said: “The state has repeatedly called on the federal government to set clear guidelines for emerging drinking water contaminants, including 1,4-dioxane, and we welcome the senators’ support in addressing this issue of national concern.”

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Dennis Kelleher, president of the engineering and consulting firm H2M in Melville and the spokesman for the Long Island Water Conference, said the industry supports the EPA doing a health evaluation “as long as it is based on science and the health risks.” The water conference is a coalition of more than 50 water suppliers and industry representatives.

The sooner a health evaluation happens, the better, said Adrienne Esposito, executive director of Citizens Campaign for the Environment in Farmingdale.

“We believe this to be a serious public health threat across Long Island,” she said.