The U.S. Coast Guard said it received a report Monday afternoon of the sinking of the 144-foot towboat. Nine crewmembers were on board when the towboat hit a submerged object near LeClaire, Iowa. All aboard were able to get off the vessel safely.
The Coast Guard estimates 100,000 gallons of petroleum products, or about 2,300 barrels, were on board the sunken vessel.
LeClaire Police Chief Shane Themas told WQAD-TV, Moline, Ill., it was unclear if any of the petroleum products spilled from the towboat.
"We can't determine how much, if any, is leaking at this point, but we're taking the precautions," he was quoted as saying Monday evening. "We can smell fuel, so we're going to go ahead and deploy the booms to contain it if it were to leak or start to leak as more water enters the vessel."
Coast Guard Capt. Byron Black, commander for the region, said the primary concern was environmental and human safety.
The Coast Guard said it was investigating the cause of the incident.