CHEBOYGAN, Mich. (AP) — Residents near a northern Michigan paper mill that caught fire Wednesday, prompting the closure of several roads and a lock and dam on a nearby river, have been told to shelter in place until Thursday afternoon as environmental officials continue monitoring local air quality.

Plumes of thick and heavy black and gray smoke visible for miles around billowed from the Tissue Depot property along M-27 in downtown Cheboygan, about 290 miles (466 kilometers) northwest of Detroit, after the fire began about 11 a.m. Wednesday.

Officials said fire crews had contained the fire to a storage building at the mill as of 4:45 p.m. Wednesday, but asked people to avoid the area as crews continue battling the fire.

Cheboygan Fire Chief Don Dailey said no mill employees or firefighters have been injured.

He said the fire started in a part of the mill where no employees were working at the time. Crews were alerted that there were several tons of plastic stored in the building, Dailey said. He said there wasn’t enough left of the damaged structure to “determine an actual cause because the roof collapsed about 10 minutes after we got here.”

“We are tearing it down as we put the fire out, so we probably aren’t going to be able to determine an official cause,” he said Wednesday.

Cheboygan residents living with a 1-mile (1.6-kilometer) radius of the Tissue Depot were told to continue to shelter in place until 1:30 p.m. Thursday “out of an abundance of caution,” the Cheboygan County Sheriff’s Department said in a Facebook post.

The U.S. Environmental Protection Agency was monitoring local air quality and EPA officials were expected to meet Thursday morning with city and county officials to discuss the air quality findings, the sheriff’s office said.

Staff with Michigan’s Department of Environment, Great Lakes, and Energy were sent to Cheboygan on Wednesday afternoon “to help assess the situation,” spokesman Jeff Johnston told The Associated Press in an email.

The nearby Cheboygan Lock and Dam, which allows boats to navigate the different levels of the Cheboygan River, was temporarily closed.

Trisha Leask, an employee at a convenience store a few blocks from the fire, said she noticed the smoke Wednesday morning.

“The smoke billowed for hours. It looked like black storm clouds,” Leask said, adding that it’s not the first time the property has caught fire.

Formerly known as Great Lakes Tissue Co., the mill once employed about 300 workers.