Authorities are again allowing boat traffic through a stretch of the Mississippi River in Louisiana that was closed while authorities searched for three people who went missing when two barge towing vessels collided, a newspaper reported.

The U.S. Coast Guard began permitting one boat at a time to travel between Destrehan and Hahnville on Monday even as the search for the three missing mariners continued for a second day, The Times-Picayune / The New Orleans Advocate said.

The two vessels collided Sunday morning near Luling, Louisiana, according to the Coast Guard. The towing vessel, RC Creppel, sank, and three crew members were missing. A fourth person aboard the vessel was rescued by a private boater.

The Coast Guard did not release the names of the missing mariners.

The RC Creppel was pushing two barges carrying sulfuric acid, and the barges broke away during the accident. One of those barges was damaged in the incident and reportedly released a small amount of vapor into the air, the Coast Guard said.

Officials said the release was later secured, and they were not concerned about any potential health risks.