UTICA, Ill. (WAND) - Illinois State police are investigating an explosion that killed three people near Starved Rock State Park in LaSalle County. 

On Thursday, May 6th at around 7:00 p.m., Illinois State Police were requested by the Illinois Department of Natural Resources to investigate an unknown explosion at the Old Illinois Route 178 bridge which is near Starved Rock State Park. 

This area is along the Illinois River west of a Starved Rock State Park boat ramp. 

The LaSalle County Coroner says it appeared the three individuals ignited a type of black powder substance along an area near the riverbank. Black powder can be used to make fireworks and was the original gunpowder. 

Three people died in the explosion, police say the events surrounding the explosion remain under investigation. 

State police say this is an isolated incident and there is no concern for public safety. 

Illinois State Police is also receiving assistance from the FBI, IDNR, ISP Crime Scene Services, Kane County Bomb Squad, LaSalle County Coroner, Utica Fire Department and the Utica Police Department.  

Anyone with information regarding this incident is asked to contact the ISP DCI Zone 3 at (815) 726-6377. Â