TOLEDO, Ohio -- Divers looking for the source of seeping oil near a sunken barge on the bottom of Lake Erie haven't located any active leaks, but they did find four open hatches on the wreckage, the U.S. Coast Guard said Wednesday.
It's not clear yet whether the open hatches could be the source of a petroleum-based solvent spotted on the surface near the U.S.-Canadian border within the past two weeks.
The substance is believed to be coming from the Argo, a tanker barge that went down during a storm in 1937 and is one of 87 shipwrecks on a federal registry that identifies the most serious pollution threats to U.S. waters.
Water samples revealed that the colorless solvent that evaporates quickly is a light to medium oil that has been exposed to the environment for quite some time, said Marvin Kimmel, a Coast Guard spokesman.
"Getting a specific chemical footprint will be difficult," he told The Associated Press.
Underwater contractors completed an initial check of the wreckage earlier this week.
The Coast Guard now is waiting on test results from sediment taken from around the four open hatches and trying to determine how to remove the hazardous cargo from the steel barge, which remains largely intact and upright, covered by a thick coating of invasive zebra mussels.
A shipwreck hunter spotted the wreckage 45 feet below the lake's surface in late August. While the barge's identity hasn't been confirmed, wreck hunters believe it's the Argo.
Historical documents contain conflicting information about what the Argo was carrying when it sank.
A report produced by the National Oceanic and Atmospheric Administration in 2013 said it was thought to be carrying 100,000 gallons of crude oil along with benzol. Research also indicates the cargo was an unknown petroleum-based solvent that was perhaps a by-product from a steel mill.
The Coast Guard told boaters to stay away from the area after crews smelled fumes in the air last month.