Two men aboard a boat when it exploded in Lake Michigan were rescued by a Good Samaritan.
"If there wasn't a boat out there, and there were very few boats out today, those guys could have gone down," Jim Schiffman, a witness told abc7.
"Lots of flames, smoke was billowing. I could see the smoke as soon as I pulled out of the harbor. And, it was probably a good two and half, three miles away before I got there," he described.
A 46-year-old man from Washington and 55-year-old man from Franklin Park were taken to Vista East Medical Center in serious condition with burns and smoke inhalation.
The 25-foot fiberglass hull powerboat burned for about 90 minutes before sinking, the sheriff's office said.
The incident is under investigation by Illinois Conservation Police.