No chemicals were detected in a rusty metal barrel that washed ashore in Oak Harbor recently.

North Whidbey Fire and Rescue investigated the barrel — labeled as containing isocyanate — on Dec. 26, found on a beach off Scenic Heights Road. Results of a sampling conducted by the state’s Department of Ecology confirmed on Monday that the liquid inside is seawater, according to Deputy Chief Ray Merrill.

Isocyanate, according to the Occupational Safety and Health Administration, is used in painting and the manufacturing of polyurethane products, like insulation, car seats and packaging material. Isocyanate is hazardous, flammable and explosive, and contains “compounds classified as potential human carcinogens and known to cause cancer in animals,” per OSHA.

North Whidbey Fire and Rescue personnel, joined by the Navy, found an opening in the barrel, spurring concern that the chemical contents leaked out elsewhere. Although the barrel still contained liquid, Merrill pointed out that if there were isocyanate inside, a chemical reaction should have occurred if it mixed with seawater.

Merrill thinks the opening in the barrel created an air pocket inside, making it buoyant enough to float from the Skagit River to Whidbey during historic flooding which hit much of Skagit and Snohomish counties early last month. High tides and strong winds may have pushed it onto the beach from the waters of Penn Cove; Merrill said a resident saw it floating there Friday morning.

Crews secured the barrel in place, left it for the night and returned the next day to conduct further tests on the liquid inside.

“We used some detectors and we got no detection of either upper explosive limits or lower explosive limits, which this product does have both of those,” Merrill said. “And we got no explosive limits at all. So we came to the conclusion that is more than likely seawater.”

Nothing could be done with the barrel until personnel were certain about what it contained, so the fire department left closed the barrel completely, secured it upright with driftwood and sectioned off the area with scene tape. The barrel has since been removed.

Merrill recommended getting the fire department involved if similar containers of potentially hazardous materials are found on the island in the future.

“You see something on the beach, it doesn’t hurt to call 911,” he said. “And it certainly does not hurt to call the Department of Ecology, because either way, we’re both gonna get involved.”

Isocyanate is used in painting and manufacturing, according to the Occupational Safety and Health Administration.

How the barrel is handled going forward depends on the results of a sampling of its contents.