Gov. Andrew Cuomo on Monday announced a $406 million agreement in principle for the U.S. Navy and Northrop Grumman to take steps to address the plume of contamination in Bethpage and surrounding areas.

Under the agreement, Cuomo's office says the U.S. Navy and Northrop Grumman will begin construction of a "network of extraction wells to hydraulically contain and remediate the contaminated plume."

Additionally, Northrop Grumman will pay a $104.4 million settlement to "advance cleanup, water supply and aquifer protection projects," Cuomo said. It marks the largest natural resource damages settlement in state history, the governor said.

The agreement is being finalized by legal teams representing New York state, the Navy and Northrop Grumman, according to the governor's office.

"For decades, one of the most critical and intractable problems for Long Island was the toxic contamination caused by the Grumman and Navy sites. With this settlement — the largest of its kind in state history — we're making the polluters pay and remedy the environmental degradation they caused," Gov. Cuomo said in a statement. "The problem was talked about for years, and many were convinced a resolution would never come, but in New York we don't back down in the fight against industrial pollution."

Cuomo said at Monday's COVID-19 news briefing that the plume was a personal issue for him for many years, back to his days as attorney general. "It was a long fight, but it will protect the drinking water for the people on Long Island," he said.

Rep. Tom Suozzi said in a statement, "This agreement with Northrop Grumman and the recent agreement with the Navy are dramatic steps forward in this 40-year nightmare. I commend the governor, the DEC, Newsday, the environmental groups and the other elected officials who have joined forces to push this plan forward. My highest praise is reserved, however, for the Bethpage Water District, who has unfairly shouldered this burden for far too long but has never failed in its mission of delivering clean water to the community it serves. I will continue to push for a requirement that Northrop Grumman pay the Bethpage Water District to acquire Plant 4 which will facilitate the cleanup and provide the water district with needed financial relief."

Officials say installment of the containment wells could begin as soon as January.