WASHINGTON (AP) — The Trump administration has stalled a study that would help regulators understand which industries dump harmful forever chemicals with their wastewater, according to two former agency officials who were involved in its development.

A public notice shows the first of its kind survey of wastewater treatment plants was submitted to the White House for approval nearly two years ago during the Biden administration — a far longer wait than is typical.

Many wastewater treatment plants receive PFAS-contaminated waste. A nationwide survey of hundreds of plants would help identify the source of that PFAS and could inform new regulations to limit their spread, according to Robert Wood, director of the engineering and analysis division in the EPA’s Office of Water before his retirement in 2024.

“If we can determine the top one, the top two, the top three” industries that dump PFAS, said Wood, “then we start work on the detailed studies and the regulation to get after nationwide limits on PFAS for the predominant industrial dischargers.”