The crew of a tugboat was quickly rescued when their vessel sank into the Mississippi River following a collision with a tanker ship in Louisiana. The U.S. Coast Guard said Monday that it is investigating the crash and that the river remains open.

St. Charles Parish Sheriff Greg Champagne said his office received a report of the collision between the ship and tugboat near the Hale Boggs Memorial Bridge in Luling, Louisiana, on Sunday night.

“Preliminary reports are that all crew members from the tug have been rescued,” Champagne said in a Facebook post around 10 p.m. Sunday.

The sheriff’s office said the tanker was traveling upriver when it struck the tugboat and caused the smaller vessel to sink, WWL-TV reported.

Emergency medical personnel evaluated the crew and would transport them to a hospital for treatment if necessary, the sheriff’s office said.

The U.S. Coast Guard’s 8th District office in New Orleans, known as Coast Guard Heartland, said it dispatched personnel to the scene but the five people who went into the river during the crash already had been rescued when the Guard crews arrived.

The tugboat, registered as the Patrick J. Studdert, sank in a stretch of river 90 feet deep, according to the Coast Guard.

The Coast Guard said there will be an assessment of possible environmental impacts of the accident site in Luling, about 23 miles west of New Orleans.