Starting Monday, Army divers will plunge into the deep water of the San Juan Islands in Washington state in search of a deadly hazard: derelict fishing nets. Hundreds of them.

Army divers, who often support joint marine missions by doing demolition, construction, reconnaissance and more, now have a mission apparently no one else can do — at least, at little or no cost to the state of Washington.

The cost of removing the nets that are deadly to marine life, and the technical skill it will take to go the depths required, were beyond what the state was prepared to handle.

Time to call in the Army.

The divers will come from the Army’s 569th Engineer Dive Detachment from Joint Base Langley–Eustis, Virginia, according to a Friday release from the Washington State Department of Natural Resources.

Army divers were at Utah Beach during the 1944 landings in Normandy, they deployed to Kuwait for Operation Desert Storm and they worked to repair ports in Haiti after the 2010 earthquake.

Their challenge now is to reach fishing nets more than 105 feet down along rocky terrain off the San Juan Islands. They’re tasked with removing the fishing nets during the Army Deepwater Derelict Net Removal project July 8-28.

The project will give Army divers a chance to train for deep-water diving operations, this time working off a contracted vessel, the release said. The mission will be part of the Department of Defense Innovative Readiness Training Program.

“This is a unique opportunity to partner with the Army to address the critical habitat for sealife in our northern waters, while service members also get the training they need to work in deep-water conditions,” Hilary Franz, commissioner of Public Lands, said in the release.

The project is a collaboration among the 569th, the state Department of Natural Resources and Natural Resources Consultants, officials said.

The deep-water nets haven’t been removed yet, the release said, because of the cost and the need for skills to do the job in deep water.

More than 230 derelict nets in deep water in the area have been found by divers, sonar and cameras.

Fishing nets are known to cause the deaths of fish, birds and mammals that get tangled in them and can’t escape.

In the shallow water of the San Juan Islands, at less than 105 feet deep, more than 500 birds, 20 mammals and 1,100 fish have been seen entangled in fishing nets, state officials say.

More than 2,200 derelict nets have been removed from the shallow water so far, most of them left from years ago when salmon gillnet fishing was prevalent, officials said.