An overpass was set aflame after a semitrailer hauling thousands of gallons of fuel overturned in Indianapolis on Thursday.
The tanker hit a guardrail on an on-ramp from Interstate 465 to I-70, which split the tank and overturned the semi, according to the Indianapolis Fire Department.
Witnesses told the fire department that the driver of the truck exited the tanker on his own with his clothes on fire. The driver, identified as Jeffrey Denman, 59, was in critical condition at a hospital.
At least two witnesses, identified as Holly McNally and Mitch Navarre, stopped to help the driver get away from the fiery wreckage.
The semi was carrying 4,000 gallons of jet fuel when it overturned, triggering two explosions that caused a much larger fire, the fire department said.
"Holly told firefighters that the jet fuel was literally pouring down the embankment as they retreated," the fire department's statement said.
Investigators believe unsafe speed contributed to the rollover.
The Indianapolis Fire Department first arrived just before 2 p.m. local time and deployed 20 units, including three tankers and a hazardous materials team. It took about 40 minutes to extinguish the flames, as firefighters had to rely on tankers to supply water because of a lack of accessible hydrants.
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Brian Harvey, an engineer with the state Transportation Department, said in a Twitter video that the debris would have to be cleared before authorities could determine whether the overpass was safe for traffic.
"Everything you're looking at here has to be moved, and then they have to bring a sweeper vehicle to sweep up all the loose material. And then we will have to make an evaluation at that time how extensive the deck's damaged and how much further work needs done before we can open it."
CORRECTION: (Feb. 21, 10:15 a.m. ET) A previous version of this article misstated the day of the tanker truck accident. It was Thursday, not Wednesday.