A barge full of more than 400,000 gallons of fuel and a heavy tanker collided in New Orleans on Wednesday, spreading a rainbow sheen of oil across 100 miles of the Mississippi River down to the Gulf of Mexico. The smell of the industrial boiler oil spread for miles, according to residents, and stands out even in a city known for its industrial accidents.

The environmental impact seems to be minimal—and the awesome flow of the mighty Mississippi will soon flush the heavy oil away—but the owners of the barge and the fuel, American Commercial Line, can take comfort in a recent court decision capping damages in any subsequent lawsuit at the actual harm inflicted. That amounts to about $300,000 at this point, according to the U.S. Coast Guard, though it will depend on how the spill affects ships trying to make it to New Orleans. So far 63 ships, including a Carnival cruise, have been stranded.

The spill is much smaller than the slicks caused by Hurricane Katrina, which led to the dumping of more than 7 million gallons of oil.