Fire Chief Roger Bates, 68, and firefighter Matthew Mahar, 25, were injured, but were alert and conscious at the scene, according to the report.
According to the The Watertown Daily Times, both men suffered significant but apparently non-life-threatening injuries, including back and head injuries.
Mahar was airlifted to Upstate Medical University in Syracuse while Bates was transported to Lewis County General Hospital with a cut to his head.
Bates was driving the tanker just after noon on Deer River Road in the town of Denmark when he says he heard a loud pop and lost control. That's when the cab detached from the tanker and went down an embankment into the river.
Officials say the volunteer firefighters were responding to a garage fire at 467 South James Street.
