PEORIA, Ill. (WMBD) — Firefighters are getting creative as the fire at BioUrja in South Peoria extends into its seventh day.

Peoria Interim Fire Chief Shawn Sollberger said things are not going the way they expected. Tuesday night, firefighters started using nitrogen foam to mitigate the fire.

“Foam is flowing from the top and back…we’re basically trying to suffocate the fire,” he said.

On Wednesday, huge plumes of smoke billowed out of a damaged silo. Sollberger said the smoke was “the worst its ever been,” and the internal temperature of the silo reached 350 degrees, the highest so far.

Sollberger warned the smoke and high temperature point to the possibility of another explosion.

“Still dealing with the possibility of a secondary explosion, secondary collapse. This is not fear-mongering, it’s just being aware of the hazards that we have and until we can mitigate this fire, we’re always going to have that risk,” he said.

In addition to foam mitigation, Sollberger said they are in contact with remote experts, who are giving them alternative suggestions on how to proceed.

“The air is feeding the fire. So we’re trying to basically close it off, no air, hopefully, we can suppress it and knock it out…Anytime you’re dealing with trapped particles, trapped dust, trapped product, you really don’t know how it’s going to shift. The foam starts to fill the cylinder which starts to move the product, and so as it starts to catch other things, that’s what we’re dealing with,” he said.

Firefighters are also continuing to use water to cool the silo. By Wednesday afternoon, the smoke appeared to subside as water flowed.

Sollberger said there is no danger to the public.