The Brief A boat explosion injured three on Lake St. Clair on Thursday afternoon. The cause of the explosion is unknown, officials say. Police say no foul play was involved. Multiple people were sent to the hospital after a boat explosion in Macomb County on Lake St. Clair. Big picture view:Deputies say at 1:10 p.m. on Thursday, officials were called to Tow Boat USA on South River Road in Harrison Township for a reported boat explosion at the gas pumps.