One person was believed to be missing after an oil rig storage platform exploded Sunday night on Lake Pontchartrain, just north and west of New Orleans.

Seven people were taken to hospitals after the explosion, and three of them remained in critical condition Monday morning, Mike Guillot, the director of emergency medical services at East Jefferson General Hospital, said at a news conference. The other four were released.

Sheriff Joe Lopinto of Jefferson Parish said at the news conference, “We are fairly confident there is an eighth person,” adding that search efforts were continuing, and the Coast Guard had contacted the person’s family.

No fatalities had been reported as of Monday morning.

The blast occurred shortly after 7 p.m. near St. Charles Parish and the city of Kenner. The platform is in unincorporated Jefferson Parish.