Massive fire breaks out at building in O’Fallon, Mo.

O’FALLON, Mo. (KMOV) - Crews battled a large fire at a building in O’Fallon, Missouri Wednesday morning.

The fire broke out around 4:40 a.m. at the Bill’s Service Center on Sonderen Street near Ft. Zumwalt North Middle School.

Clean-up was underway Wednesday at Bill’s Service Center. Workers did not want to go on camera but tell News 4 the fire was contained to the warehouse, meaning most of the damage was to new inventory.

O’Fallon Fire Protection District Battallion Chief Brian Moore says the fire was already through the roof when they arrived.

“We wanted to make sure we took precautions to have a safe collapse zone set-up around the building that way if and when the building collapsed, which it did, our firefighters were safe,” Battalion Chief Moore says.

Peter Jackson was driving home from work when he saw dozens of firefighters outside the business.

“Flames had to have been maybe 100 ft high,” Jackson says. “They were really big flames.”

Multiple agencies responded to the fire.

“I was rather concerned it was going to start spreading out farther but because there were so many fire trucks around, I felt pretty safe,” Jackson says.

Battallion Chief Moore says the cause of the fire has been ruled accidental.

Fire officials say the owner’s son was inside when the fire started, he made it out safely.

When the fire happened, Battalion Chief Moore says the worker tried to put the fire out himself, was unsuccessful and then called 911.

Firefighters said the blaze was a fuel-led fire with explosions; there was also a partial collapse.

Battalion Chief Moore says those explosions most likely came from the gasoline tanks on lawn mowers.

“Because of the volume of fire and the potential hazards that were in the building, structure was unsafe when we pulled up to send any of our firefighters inside of so chose a defensive position,” Battalion Chief Moore says.

Jackson was watching this unfold when those explosions happened.

“Enough of a boom to kind of put a little press on my chest,” Jackson says. “It didn’t knock me back or anything but definitely something big exploded and flames started pouring out of the front really bad.”

North Middle School has canceled classes as a result. All other Ft. Zumwalt schools remain open Wednesday.

The business tells News 4 it hopes the primary shop will be open to customers again on Thursday.

Bill’s Service Center posted online that two customers mowers were impacted by this fire, saying they plan to call those customers within the next 48 hours.