Factual error: In the beginning of the movie, the explosion in the Holland Tunnel is caused when a car crashes into the trucks carrying toxic waste barrels. In real life, it is against the law for vehicles carrying hazardous chemicals to use any of the tunnels. Even if the drivers didn't know this, which is highly unlikely, they would have been pulled over by the Port Authority cops as soon as they headed for the entrance - lots of yellow barrels would be a bit suspicious.
Factual error: Even if the survivors were in their vehicles, a raging inferno like that would seriously damage their skin. Even if a vehicle can protect you from being set on fire, I think the chances of being skin burned and blistered are especially high. First of all, the prison bus had those open diamond holes on the side of the bus. Also, I believe someone's car window was open, so they should have been set on fire.