TOLEDO, OHIO: A tanker barge found on the bottom of Lake Erie near the US-Canadian border may be the remains of a vessel loaded with oil or some type of solvent when it sunk nearly 80 years ago and now is on a federal list of wrecks that could pose a pollution threat, shipwreck hunters said Saturday.

The US Coast Guard said it is investigating a small leak spotted near the wreckage just in the last few days, although it's not clear whether it's an ongoing leak or what kind of substance might be coming from the barge.

"We're fairly certain there's a leak," said Cmdr. Anthony Migliorini, who leads a Coast Guard marine safety unit based on the lake. "It's really hard for us to point to a specific cause."

It would be a significant discovery if the wreck turns out to be the Argo, one of 87 shipwrecks on the federal registry created two years ago to identify the most serious pollution threats to US waters.

Like about half of the wrecks on the list, the Argo's exact whereabouts have been unknown since it went down during a storm in 1937 in western Lake Erie — about midway between Toledo and Cleveland.

Shipwreck hunter Tom Kowalczk, who lives along the lake, discovered the barge in August while he was searching for a wooden schooner that sunk in 1845 between Ohio's Kelleys Island and Pelee Island in Canada.

Using a side-scan sonar, he eventually saw clear images of the barge, including deck fittings and a tow line.

"I knew right away it was the Argo," he said. "Then I thought 'what's it doing here?'"

Most shipwreck hunters had long-thought the Argo was a few miles to the north in Canadian waters.

While the barge's identity hasn't been confirmed, researchers with the Cleveland Underwater Explorers are virtually certain it is the Argo, said Christopher Gillcrist, executive director of the National Museum of the Great Lakes.

Divers took measurements on Friday that matched the Argo's dimensions listed in historical records after an earlier evaluation of the wreckage raised questions about its identity, Gillcrist said.

One other thing that suggests the wreckage is the Argo is that there are no reports of another tanker barge being lost in the same area, he said.

No matter the answer, the Coast Guard said its priority is to find and seal the source of the leak and determine if the barge holds any cargo that could cause an environmental mess in the shallowest of the Great Lakes.

Divers who examined the wreckage on Wednesday didn't notice any leaks at that time, Migliorini said. And there have not been any reports of large spills in the area.

A Coast Guard helicopter on Saturday spotted an area of discoloration in the water that was the length of about four football fields while crew members in a boat reported smelling an odor in the air, he said.