Witnesses said more than a dozen people tried to free the man, some carrying blankets and jackets to smother the blaze.
"They were trying to get him out of the cab, but everybody who tried would be stopped by the flames," Gregory Coleman told The Republican newspaper of Springfield. "There were just a bunch of people running towards the fire. It was crazy."
Coleman's sister, Rebecca Coleman, said the tanker then exploded.
"The explosion just rocked the whole bridge," she said. "The car bounced."
The fire engulfed three cars and pushed the truck partially off an Interstate 91 overpass, said Peter Judge, a spokesman for the Massachusetts Emergency Management Agency.
State police said a car lost control on the highway and hit another car and the tanker. The tanker then veered off the road, striking a guardrail and sign post.
The trailer separated from the tanker, rolled over the guardrail and down an embankment as the cab and trailer burst into flames, police said.
The truck driver, Aaron J. Staelens, 43, of Richmond, N.H., was eventually rescued and taken to Massachusetts General Hospital in Boston, where a spokeswoman said he was in critical condition Friday night. He suffered third-degree burns over much of his body, The Republican reported.
The driver of the initial car, which was later struck by yet another vehicle, was taken to a local hospital with minor injuries. No other injuries were reported.
Staelens works for Abenaqui Carriers of North Hampton, N.H. A driver for the same company rolled over a fuel tanker in Everett in December, sparking a fire that severely damaged several homes and destroyed dozens of cars. That driver was not cited.
A spokesman for Abenaqui said he did not have further details.
Diesel fuel spilled on the highway after the crash around 9:30 a.m., but Judge said the accident happened on an area of the highway that is relatively isolated and he did not expect homes or businesses to be affected.
The fire was still burning more than 90 minutes after the crash, and smoke could be seen for miles. The blaze seemed to be "flowing like lava," said Charles Swider, a Chicopee alderman.
"It looked like the world was on fire," he said.
The blaze was out by about 11 a.m. Some lanes of the interstate had opened by the afternoon.