Gov. Andrew M. Cuomo on Wednesday ordered Northrop Grumman and the U.S. Navy to give the state and a local water district access to monitoring wells that track groundwater plumes flowing from a former Bethpage manufacturing site.

The contamination has moved more than 3 miles south of Bethpage, and for decades the state, nearby water districts, the Navy and Northrop Grumman have wrangled over how to clean up the toxins spreading through the aquifer. The contaminants have been traced to military manufacturing operations conducted by the two dating back to the 1940s.

“There have been too many questions about the extent of contamination caused by this plume and residents are frustrated with the lack of answers from the Navy and Northrop Grumman,” Cuomo said in a news release. “This action will allow us to develop an action plan to ensure that the health and safety of this community is protected.”

VideoState to test wells monitoring toxic plume in Nassau

The Navy and Northrop Grumman did not respond Wednesday to specific questions about Cuomo’s order.

The executive action came two days after Sen. Chuck Schumer (D-N.Y.) held a news conference about the plumes, calling the Navy’s and Northrop Grumman’s earlier responses a stalling tactic.

In November, the Massapequa Water District had asked for access to five to seven wells to perform a type of analysis that could essentially fingerprint the contamination, with a focus on the carcinogenic solvent trichloroethylene.

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Navy and Northrop Grumman officials, in December and earlier this month, said sampling at more wells would give a better picture of contamination. They also had questions about the science behind the testing.

Under Cuomo’s order, the state Department of Environmental Conservation will conduct its own water-sample testing in Massapequa. The timing of that was not clear Wednesday.

Cuomo’s office and the DEC did not respond to questions about the order.

Schumer on Wednesday praised the state “for stepping up to the plate and delivering just the kind of real information and access to test wells that the Navy and Northrop Grumman had been stonewalling the districts on.”

DEC will collect and test samples at six monitoring wells, using a technique called compound specific isotope analysis to identify the composition of a contaminant. In addition, Massapequa will be allowed to do its own analysis.

Additional testing also could be required.

The sites formerly used by the Navy and what now is Northrop Grumman were added to the state Superfund program in the 1980s and have been subject to several cleanup plans.

Water officials and local politicians say the plumes put drinking water supplies of 250,000 people at risk. Ongoing treatment is in place for some affected water supplies in Bethpage, South Farmingdale and Levittown, though districts have complained that handling of the cleanup has been slow.

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“If this is a means to an end and it gets Massapequa information soon, then that’s a good thing,” said Richard Humann, president and CEO of H2M architects + engineers, which represents water districts. “The water suppliers can use all the help they can get.”

Wells in Massapequa have not been hit by the contamination, but it inches closer each day. The district wants to see if a correlation exists between what is found where the plume began and what is showing up farther away in monitoring wells, water district superintendent Stan Carey said.

“We are pleased that the governor intervened and invoked his executive authority,” Carey said. “We’re looking forward to getting this done and analyzing the results.”

The state typically uses test results supplied by polluters, if those responsible are known, but New York does have the right to do its own sampling, said Manhattan attorney Lawrence Schnapf, who specializes in environmental law.

“The state superfund law does provide authority for DEC to come onto property to collect samples,” Schnapf said. “This happens more often when an impacted property owner refuses to allow access, but is not unprecedented.”