BURLINGTON, Wis. (AP) -- Smoke and flames poured Thursday from a southeastern Wisconsin food processing plant, where dozens of firefighters battled a blaze all night in frigid temperatures.

Hazardous materials handlers have secured the area where ammonia and liquid oxygen tanks are stored at the Echo Lake Foods egg processing plant near downtown Burlington, Mayor Bob Miller said.

Police evacuated 10 homes and one apartment building near the plant, according to police and the mayor. Employees evacuated the plant safety when the fire broke out about 6 p.m. Wednesday and no firefighters have been hurt, Miller said. The fire was still burning as of 8 a.m. Thursday.

Firefighters from more than 80 fire departments from southern Wisconsin and northern Illinois took turns in fighting the raging blaze at the 70,000 square foot building. The cause of the fire is under investigation, fire officials said.

Miller said the egg processing plant has been expanded several times since it was founded in 1941, making the fire at the patchwork factory difficult to control.

Echo Lakes Foods employs about 300 people at the Burlington facility, making it one of the city's largest employers.

"This will affect the city greatly, as well as obviously Echo Lake," Miller said. "We will attempt to work with the owners of the company, with the Wisconsin Economic Development Corporation and with the Racine County Development Corporation in an attempt to help them rebuild and reopen the plant as soon as possible."

Copyright 2013 The AP.