PEORIA- Residents in Peoria and the surrounding area were rocked by an explosion early Wednesday morning at an ADM corn processing plant.
The blast was so strong it knocked out windows of surrounding businesses, but most of the damage was contained to the plant itself.
People who were awake at the time say they heard the explosion.
"I just heard it, I heard a loud 'boom,' said Tyler Willis, who lives on North Imperial Drive in Peoria.
"I thought we were under attack," he said.
"I heard this big boom," said Ira Carrier, who lives on Vine Street in Peoria.
Carrier said he thought the sound came from something else.
"Like a big wreck you know, big semi is what it more or less sounded like," Carrier said.
What these two men likely heard was the early morning explosion at ADM. The Peoria Fire Department says it got the call around 3:45 a.m and that crews rotated in shifts all day to keep it under control.
"The explosion itself or somewhere in the mix it caused a couple of other fires within their facility," said Division Chief, Ed Olehy.
Olehy said after the initial fear of a second explosion, multiple fires and a collapsed roof made it even harder to fight. No one was significantly hurt, but Olehy said the facility is looking at a lot of repairs.
"I'm expecting this to be in the millions of dollars of damage," Olehy said.
An expensive boom that sparked concern across town.
"I jumped on facebook and I saw other people posting, did you hear that too?" said Carrier, showing off his Facebook and Twitter.
Willis said, "it was kind of long sounding, from the distance I was, it kind of echoed. It was just something I've never heard before."
These two men who said they heard the blast live in Peoria, WMBD 31's Facebook Page was flooded with people saying they heard the explosion from as far away as Creve Coeur, Washington and Pekin.
ADM says it's halting operations until further investigation.