A fire broke out at the Waco Wood Recycling & Materials Plant shortly before 1 p.m. Wednesday.

Fire officials at the scene said the flames were caused by an internal combustion at one of the plant's mulch pits, which are located at 268 Antler Road in Waco, near the intersection of Antler Road and McLaughlin Road.

The Speegleville, China Spring, Valley Mills, Waco and McGregor Fire Departments were all dispatched for assistance, battling the flames, which initially spread more quickly that crews could contain. Nearby homes were evacuated, after an early scanner report described one of the plant's structures as "fully involved."

Pallet piles quickly caught fire, as first responders worked to move heavy equipment to minimize exposure, according to the Waco-McLennan County Office of Emergency Management. Emergency Management Coordinator Frank Patterson sent a handful of fire corps volunteers to care for first responders, who were not just fighting the flames -- but also battling intense heat and windy conditions. Heavy winds only made containing the fire more difficult, officials said.

No major injuries were reported. But, first responders confirmed several of the plant's employees were treated for spoke inhalation.

PHOTOS: Fire at Waco Wood Recycling & Materials Plant

Fire officials said they had been to the plant several times in recent weeks to monitor an ongoing burn, but on Wednesday the burn got out of control. Neighbors across the street said the site had been visited multiple times by environmental agencies and fire departments. Some of them said the fire was a "disaster waiting to happen."

It was not immediately clear how long the fire would burn, but firefighters said they would continue to battle it overnight. A Speegleville firefighter told reporter Chris Rogers "there's probably not enough water in McLennan County to put this thing out tonight."

Channel Six spoke exclusively with a family member of the man who owned the plant's property. She said everyone was on lunch break when the fire broke out.

"We pulled in and saw just clouds of black smoke and then flames and we knew something was wrong," the woman, who did not wish to be identified, said.