The spill late Tuesday was estimated to be up to 8,000 gallons of a petroleum-based substance called cumene, said Maggie Carson, a state Environmental Protection Agency spokeswoman.
The spill did not appear to pose a serious threat to residents or marine life, and there were no evacuations, said Lt. Wayne Chapman, a spokesman for the Coast Guard.
Kirby Inland Marine, the Houston-based owner, said the barge hit the guide wall of a lock that helps manage water flow. State officials earlier said it had run aground.
Company spokesman Mark Buese said nobody was injured and the spill did not present a risk to human health.
"I would say it's not particularly dangerous," he said.
Contact with cumene can irritate skin and eyes, cause headaches in humans if inhaled, and be damaging to animals directly exposed to it. It is used in a variety petroleum products, manufacturing, as a paint thinner and as a component of high octane fuels, according to the EPA Web site.
The barge was en route from the Gulf of Mexico to a port somewhere in the Midwest, Buese said.
Traffic on the Interstate 24 Ohio River Bridge was restricted to one lane to enable officials to set up an air monitoring station on the bridge. It was reopened Wednesday afternoon.
As a precaution, local authorities also requested that nearby Fort Massac State Park be closed.