A man was killed in downtown Nagoya early Thursday after a payload of 7,000 spray cans exploded when the truck they were on smashed into his station wagon, police said.

"Cans burst into the sky like popcorn making loud noises," said a taxi driver passing near the scene.

The explosions damaged buildings and jammed surrounding roads.

Taro Kowaki, a 38-year-old company owner from Nagoya's Atsuta Ward, was killed after the truck collided head-on with his vehicle at an intersection in Naka Ward at around 6 a.m. The collision caused a fire that triggered the blast, police said.

The truck driver, Yoshimichi Aoyama, 35, from Toyota, Aichi Prefecture, was not injured.

Police suspect the collision was caused by one of the vehicles running a red light.

Flames rising more than 10 meters engulfed the truck, and pieces of spray cans littered the surrounding area, with some found on the rooftop of a neighboring 11-story building, according to witnesses.

Investigators and firefighters closed the intersection for about seven hours, causing traffic jams around the site.