SENECA, Ill. (WCIA) — 14 people were hurt on Saturday when an explosion occurred on a boat moored in the Illinois River.

The explosion happened at Springbrook Marina in Seneca. Officials said that at approximately 4:20 p.m., a 40-foot boat with 17 people on board had just completed fueling when an explosion happened inside the vessel, which subsequently sank.

13 of the people on board had to be taken to the hospital for treatment of injuries, and one was injured critically enough that they had to be flown to Chicago. A marine employee was also injured by the explosion.

The river is still open, but boaters are urged to drive near the site with caution; the sunken boat has not been removed from the water yet. Authorities and representatives with the U.S. Environmental Protection Agency are at the scene on Sunday assisting with recovery operations, which are expected to be complete sometime Sunday afternoon.

The Illinois Conservation Police is leading the investigation with assistance from the Illinois State Police and Illinois State Fire Marshal’s Office.