The lawsuit, filed in federal court, names Nave Shipping SA, the tanker's owner, and Thome Ship Management, its management company, as defendants. It alleges that the collision occurred "as a result of the negligence, gross negligence, fault or carelessness" of the companies.

The Atlantic Asphalt tanker struck the American Heritage paddleboat at about 12:30 p.m. Friday as the cruise ship was docked at the Thalia Street terminal for passenger disembarkation. Nearly 200 people were on board the American Heritage at the time. The impact left the vessel on its side and partially submerged. All passengers and crew survived, including more than 100 who were rescued from the river, a outcome that led New Orleans Mayor Helena Moreno to call the incident "the miracle on the Mississippi."

Thirty-two people were taken to hospitals, none with critical injuries. As of Saturday, eight remained hospitalized, two in serious condition.

The port's lawsuit states that physical damage to the terminal is currently estimated to exceed $1 million, with additional substantial direct, indirect and consequential damages anticipated. The port also expects to incur costs for cleanup, surveys, repair, replacement and salvage.

On Friday, port officials requested that the tanker be seized and sold to cover the costs of the damage. A federal judge approved the seizure request.

The Atlantic Asphalt has since been towed away from the site, but officials said it could take weeks to fully remove the American Heritage. Coast Guard Capt. Melanie Burnham said operations are now focused on fully reopening the river and safely removing hazardous material from the cruise ship, which is estimated to hold 160,000 gallons of fuel.

"We're going to have divers in the water so they can do a full assessment on what's the right path to be able to remove it," Burnham said. "We also have teams that have been deployed throughout the entire area, the river system to monitor the area for any pollution." Boat traffic restrictions remain in place along the Mississippi.

The exact cause of the crash is still unknown, though Burnham said the tanker appeared to have a steering issue. The National Transportation Safety Board is investigating. NTSB board member John DeLeeuw said the tanker's voyage data recorder was recovered and will provide information on speeds and maneuverings, similar to an aircraft's flight data recorder. A preliminary report is expected within 30 days, with a final report on probable causes and safety recommendations expected in 18 to 24 months.

The collision has raised concerns about safety and environmental risks on a waterway that is central to the region's economy and ecology. The port's legal action signals its intent to hold corporate operators accountable for damages to public infrastructure, even as the investigation into the cause continues.