PHILADELPHIA (AP) - The driver of a tractor-trailer hauling gasoline lost control on an off-ramp and flipped the tanker truck on its side in a wreck that set it afire and destroyed a section of the East Coast’s main north-south highway, Pennsylvania’s top transportation official said Monday.

In the first official accounting of a wreck that threw hundreds of thousands of morning commutes into chaos and disrupted untold numbers of businesses, state Transportation Secretary Mike Carroll said the driver was northbound “trying to navigate the curve, lost control of the vehicle, landed on its side and ruptured the tank.”

The driver was feared dead, and a relative of a New Jersey truck driver who has not been heard from since Sunday told The Philadelphia Inquirer that investigators had contacted the family in an effort to identify human remains recovered from the wreckage.

Pennsylvania State Police said a body was turned over to the Philadelphia medical examiner and coroner, but did not identify the remains or respond when asked if they belonged to the driver.

Gov. Josh Shapiro, speaking of those on the roadway and not the trucker, said he “found myself thanking the Lord that no motorists who were on I-95 were injured or died.”

Interstate 95 will be closed in both directions for weeks as the summer travel season kicks into high gear. The elevated southbound portion of I-95 will have to be demolished, as well as the northbound side, Carroll said. Motorists should avoid the northeast corner of the sixth-largest city in the country, transportation officials said.

The accident also disrupted the automotive route from Canada to Florida through the Boston, New York and Washington metropolitan areas, increasing Americans’ dependence on air travel and on the interstate rail network.

Videos shared on social media showed a number of close calls around the accident, with people driving through the area as flames licked upward from the fire below.

The National Transportation Safety Board was on the scene Sunday night. Federal investigators have been collecting information about the truck and talking with the company and emergency responders in order to understand the sequence of events. They are expected to make a preliminary report within weeks.

The damaged I-95 segment carries about 160,000 vehicles daily, Carroll said. State police don’t know if the driver was speeding, and no other vehicle has been found. Officials said they had been in contact with the trucking company, but they did not identify it.