NILES — A fire at a Michigan factory Thursday grew out of control and sent chemicals into the air, forcing dozens of people from their homes.

Fire investigators said sanding equipment may have caused the fire at Michigan Composites in Niles Township. Eleven departments from Indiana and Michigan were battling the fire.

Two chemicals changed the dynamics of the blaze. The fire chief said the chemicals are not extremely harmful alone, but they are hazardous when mixed together, causing breathing and skin irritation. Crews had to evacuate a three-mile radius around the area.

“I heard all of the sirens this morning but I didn't know where they were going,” Deanna Whaler told WSBT News.

Not only were the plumes of smoke or intense flames a danger for firefighters and employees working inside Michigan Composites, two chemicals known as isocyantes mixed with the fire put the environment at risk.

“They just kept going and going,” Whaler said, “so I knew it was pretty big.”

“It’s not extremely harmful, but it is a hazardous chemical,” said Niles Township Fire Chief Gary Brovold as he briefed reporters Thursday afternoon.

The four-alarm blaze was forced to continue burning once firefighters recognized something was in the water runoff.

“We’re monitoring the situation,” Brovold told reporters. “We’re trying to contain all of the runoff from the fire so that it’s contained right here on the property.”

Hazmat crews were called and Third Street and Bond Street from Fort Street to Beeson Road was blocked off.

“We had to shut the operations down,” explained Sgt. Corey Burks of Berrien County’s Hazmat team. “We conferred with the command on this, shut operations down while we reinforced that dike back there in order to catch the runoff so that there wasn’t a large amount of runoff back there.”

“With the hazardous materials, they closed the roads and they just had everyone evacuate for safety precautions,” explained Sgt. Greg Edgerle with the sheriff’s department.

“They say they saw about 100-foot flames as they were passing by, but they had it all blocked off where you couldn't come through,” said Taylor Wilson.

Evacuees who were forced out were sent to the Niles Fire Department as crews worked to fight the fire.

Crews continued to work on extinguishing the fire once the water runoff was contained, but shifting winds were still a concern.

At about 1 p.m. the fire was mostly contained, but several hot-spots continued to burn.

Fire officials say the risk of contaminating the river and groundwater is minimal.

“We had a representative from DEQ down here to also monitor the situation,” Sgt. Burks said. “At this point it looks like the retention pond behind this facility here did what it was supposed to do.”

The building is a complete loss.