The mine that was discovered floating in Puget Sound was from an exercise conducted at Naval Undersea Warfare Command, Keyport in 2005.
During the exercise, inert mines were placed between Brownsville, Keyport, and Bainbridge Island, according to Sheila Murray, a public-affairs deputy at Navy Region Northwest.
Not all training mines were recovered.
A diver for the Washington State Department of Natural Resources was working in the area Tuesday when he stumbled across the rusty mine.
"It was unusual and that’s part of our job is to look for hazards to navigation, so I came back to take a look at it," said Jim Shannon, who dives down and checks on underwater leases for geoduck shellfish harvesting.
As he got closer Tuesday morning, he realized what it was and made calls into the Coast Guard and then the Navy.
“It looks exactly like the things you see on TV – that looks like a mine, and I thought to myself that doesn’t look good," said Shannon. "It doesn’t look like anything I’ve seen on the water before. I’m familiar with buoys, I’m familiar with derelict vessels, things like that.”
“This definitely was not floating garbage.”
Shannon said the object had clearly been in the water for some time, maybe even decades, according to Navy officials.
The mine was detonated without incident in the water after two Navy divers with the Explosive Ordnance Disposal team secured it.
Shannon said he was very impressed with the actions of the Navy and the Coast Guard.