(Image Credit: Kyodo News/AP Photo)

TOKYO - Japanese officials ordered the immediate inspection of dozens of tunnels across the country, a day after concrete ceiling panels collapsed in central Japan, killing at least 9 people.

The accident at Sasago Tunnel Sunday morning sparked a blaze along a 3-mile passage on a major highway, crushing at least 3 cars and trapping passengers inside. Rescue crews overnight pulled the charred remains from cars.

Five victims, all in their 20s, were trapped inside a rental van. The body of a 50 year-old truck driver was pulled from the cab, hours after he made a desperate call to co-workers for help.

Firefighters said heavy smoke hampered efforts to reach the victims.

"I couldn't read the measuring device, or see my feet because of all the smoke," one firefighter told reporters. "When we heard an explosion deeper inside the tunnel, we decided we had to retreat."

Aging "anchor bolts" that came loose likely caused the 1-ton concrete slabs, as many as 150 of them, to collapse, officials with tunnel operator Central Japan Expressway Co., or NEXCO, said at a news conference today. The screws used to hold metal rods that suspended ceiling panels above the road and through mountains were installed when the tunnel was built 35 years ago.

The structure had undergone a detailed inspection in September, but the actual ceiling was not thoroughly checked because it was 16 feet above the panels, NEXCO officials said.

The accident has raised questions about the safety of other aging roads and tunnels in Japan, many of them built during the construction boom of the 1960s and '70s.

The Transport Ministry ordered that immediate inspections be carried out at 49 other highway tunnels around the country that were similarly constructed.

Witnesses describe a frantic scene Sunday morning, as the panels began to fall, one by one. Many ran to safety, as the smoke billowed through the tunnel, 2 miles from the exit.

NHK reporter Yoshio Goto, who narrowly escaped disaster, said it felt like he was witnessing "computer graphics in a 3-D movie."

He was driving in the left lane, when the ceiling came crashing down on the passenger side of his car.

"[The ceiling] looked like it was alive, like a snake," Goto said. "I can't describe the sounds I heard. I shudder to think what would've happened if I was trapped inside."