PORTLAND, Ore. (KOIN) — Firefighters are battling a fire burning in an abandoned building in Northeast Portland late Wednesday morning, according to Portland Fire & Rescue.

The blaze broke out in the vicinity of Northeast 100th Avenue and Northeast Irving Street just before 10:30 a.m. PF&R said firefighting efforts will be a “slow rollout” since the building has previously been deemed unsafe.

The department told KOIN 6 that the building is listed on the unsafe building registry, which is comprised of buildings across the city determined to be hazardous. These buildings are marked with a large “U” signifying that it’s unsafe for firefighters to enter in the event of a fire.

Even though these buildings have been determined to pose a risk to firefighters, PF&R spokesperson Terry Foster told KOIN 6 in 2021 that some of the buildings listed are still being used.

“Some of these buildings that are deemed unsafe are still occupied for businesses and things like that, but if it’s an immediate danger to people, we can go through the process of ‘Hey it’s not even safe for you to be in this building’ and we need to work on that,” Foster said.

Fire officials have not said what sparked the blaze.