Dense fog contributed to a fiery chain-reaction crash Saturday involving 71 cars, vans and trucks on the Sam Houston Tollway. As many as 30 people were taken to hospitals, but there were no deaths, police said.

The pileup started just before 7 a.m. on the four-lane highway and involved traffic in both the eastbound and westbound lanes.

"It was kind of a wall of fog," said Mike Young, 45, who was driving to work. He said he climbed out of his sport-utility vehicle to safety while hearing crash after crash.

"When everyone was getting out, you could smell the gas and knew there would be a problem," Young said.

The wreckage prevented firefighters from reaching the blazing vehicles, said Kenneth Fontenot, whose SUV was destroyed in the flames.

Roger Ealey said he dove out of his car when he saw it was about to ram a pickup that had no lights. He suffered minor injuries and his car became lodged under the pickup.

"You couldn't see anything" because of the fog, said Ealey, 27, of Missouri City.

Capt. Ray Valenta of the Harris County Constable's Office said 36 cars wrecked in the westbound lanes and 35 wrecked in the eastbound lanes on the highway in southwest Harris County.