After 14 years of delay Northrop Grumman Corp. has signed a state cleanup plan and agreed to take legal responsibility for removing toxins from a Bethpage groundwater plume that traces its roots back to decades-old contaminants from aviation, weapons and space exploration manufacturing.

The document sets clear reporting deadlines. By May 21, Northrop Grumman must submit a report detailing the effectiveness of on-site treatment systems used to remediate the plume. By June 20, the defense contractor must also file a work plan detailing how it will monitor the plume, which has spread more than 4 miles from its starting point, and how it will operate, maintain and monitor on-site treatment systems.

While the defense contractor had undertaken many of the demands -- such as funding the monitoring and treating of the plume -- included in the 2001 cleanup plan, the document had gone unsigned, making it hard to enforce, state Department of Environmental Conservation officials said.

"This consent order is a significant step forward to ensure that the responsible parties take action to identify, contain and clean up the groundwater contamination associated with the Bethpage plume," DEC Commissioner Joseph Martens said.

Financial details were not disclosed.

Plainview resident David Sobolow said the requirement for Northrop Grumman to provide information to the state was welcome because very little is known about the company's actions.

"Here's this community that's been struggling to get answers for a long time," said Sobolow, community co-chair of the Navy Restoration Advisory Board, which connects community members in restoration areas with the Navy. "We get nothing from Grumman."

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Under the agreement, Northrop Grumman does not admit liability for the contamination. But the state can take action in federal court if work is not performed, the DEC said.

Northrop Grumman did not respond to a request for comment.

"I think it's long overdue," Bethpage Water District Superintendent Michael Boufis said. "We feel this is the first time that they're acknowledging, and signed onto that there's a potential problem out there."

Sen. Charles Schumer (D-N.Y.), who pressured the EPA to intervene and order Grumman to sign the plan after months of delay, said the news was good, but more needed to be done.

"Grumman took much too long to sign this consent order, but the fact that we finally have their signature brings us one step closer to righting the wrong of contamination -- and holding Grumman's feet to the fire for an expeditious remediation plan," Schumer said.

Soil and groundwater contamination has long plagued the area.

What is now Northrop Grumman Corp. began engineering, manufacturing and research development operations in Bethpage in 1936, with the Navy following on nearby property in the 1940s. The Navy owned the land, but Northrop Grumman was the operator.

Contamination was first documented in the late 1940s. In 1983, the state added 600 acres of the Navy and Grumman properties to the state Superfund program. Separate plumes have been documented over the years, and three cleanup plans have been issued to deal with the contamination.

The Navy signed a similar cleanup document in 2003 outlining remediation, but Grumman did not. The two entities have been wrangling over responsibilities, state and federal officials said.

The DEC and EPA began to put pressure on the defense contractor last year to sign the document after the Navy disclosed it had found levels of the degreaser and carcinogen trichloroethylene at 4,600 parts per billion about 2,100 feet from a Bethpage Water District well. The drinking water standard is 5 parts per billion.

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The document also orders Northrop Grumman to cooperate with the Navy on efforts to delineate that hot spot of contamination.

"It's a step in the right direction," Boufis said.

Timeline of the Plume

In the 1940s through 1998, the Navy and what is now Northrop Grumman operated manufacturing facilities on a 609-acre site in Bethpage. Here is a history of the contamination that occurred from the plant:

-- 1947. Chromium found in groundwater south of the Grumman site.

-- 1986. Nassau County reveals shallow plume of contamination sinking and moving southeast from the sites.

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-- 2009. A more contaminated, deeper plume is found coming from Bethpage Community Park.

-- 2012. DEC issues cleanup plan for park plume.

-- 2013. Contaminants from plume discovered in two Levittown wells, which are closed, near Wantagh Avenue and Entry Lane.

-- 2014. The Navy reveals high levels of trichloroethylene, TCE, discovered and Gov. Andrew M. Cuomo signs legislation ordering review of cleanup plan.

-- February 2015. The Navy and Northrop Grumman probe groundwater quality north of Hempstead Turnpike and north and south of the Southern State Parkway.