An investigation is underway after a massive Port Kells industrial fire sent one man to hospital in Langley, and shut down the Golden Ears Bridge at rush hour on Tuesday.

A series of explosions occurred at the maintenance garage of Ken Johnson Trucking, a company that trucks chemicals and fuel, about 2:30 p.m. PT.

One employee who was caught in the blasts is being treated for burns to most of his back. Four others in the building were not injured.

Five tanker trucks were destroyed and a three-bay truck workshop burned to the ground in the fire.

"There's tanker parts all over the back lot," said Langley Asst. Fire Chief Bruce Ferguson. "That happened before our arrival."

Owner Ken Johnson said the tankers were empty of the fuel they often carry and the huge pillar of black smoke was generated by burning tires, not flammable liquids.

"It was a series of explosions, because a shop contains acetylene tanks and propane tanks and we had certain things in the shop, plus the tires. Once a tire lets go, it lets a big bang," Johnson said.

Port Kells, B.C.

One tanker truck full of isopropyl alcohol on the property did not explode.

"I’m definitely relieved. It had the potential of being a lot worse," said Ferguson.

Police said later that unknown chemicals stored at the depot triggered the initial blast that set off the chain of smaller explosions.

With files from the CBC's Natalie Clancy