Navy blows up decades-old mine discovered floating in Washington's Puget Sound

Bomb technicians from the Navy detonated a "dated military mine" on Tuesday that was found floating for hours in Washington's Puget Sound between Brownsville Marina and Bainbridge Island.

The Navy said in a statement the object was reported about 2 p.m., and an inspection showed the mine had decades of marine growth on it. Officials said they detonated the mine at 8:04 p.m.

"The detonation did not create a secondary explosion, which indicated the device was inert," the Navy said in a statement. "Its origin remains undetermined. The Navy will continue to investigate."

Video from KIRO-TV shows the moment the bomb was detonated.

The discovery of the device prompted the Coast Guard to set up a 1,500-yard safety zone before the Navy inspected the device and towed it out to a safe area for detonation. The Coast Guard said the ordnance was originally located by a Washington State Department of Natural Resources crew.

A pair of U.S. Navy divers attach a rope to a "reported unexploded ordnance" drifting in the water between Brownsville Marina and Bainbridge Island, off Brownsville, Wash., Tuesday, Aug. 28, 2018. Brownsville is located a few miles south of Naval Base Kitsap - Keyport's torpedo testing range. The Navy was not immediately able to respond to a request for information. (Meegan M. Reid/Kitsap Sun via AP)

A pair of U.S. Navy divers attach a rope to a "reported unexploded ordnance" drifting in the water between Brownsville Marina and Bainbridge Island, off Brownsville, Wash., Tuesday, Aug. 28, 2018.  (Meegan M. Reid/Kitsap Sun via AP)

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Authorities also asked residents along the waterfront to stay inside and away from beaches as a precaution.

A U.S. Coast Guard boat keeps watch over a "reported unexploded ordnance" drifting in the water between Brownsville Marina and Bainbridge Island, off Brownsville, Wash., Tuesday, Aug. 28, 2018. Brownsville is located a few miles south of Naval Base Kitsap - Keyport's torpedo testing range. The Navy was not immediately able to respond to a request for information. (Meegan M. Reid/Kitsap Sun via AP)

A U.S. Coast Guard boat keeps watch over a "reported unexploded ordnance" drifting in the water between Brownsville Marina and Bainbridge Island, off Brownsville, Wash., Tuesday, Aug. 28, 2018.  (Meegan M. Reid/Kitsap Sun via AP)

"It's just an unusual situation, not many times you see a World War II mine floating around Brownsville Bay," one resident told Q13 News as he checked out the situation.

Brownsville is located a few miles south of Naval Base Kitsap — Keyport's torpedo testing range.

The Associated Press contributed to this report.

Travis Fedschun is a reporter for FoxNews.com. Follow him on Twitter @travfed