A large fire broke out Sunday afternoon at the vacant Centennial Mills building in Portland’s Pearl District, sending heavy smoke into the area.

Fire crews responded to the warehouse but avoided entering the structure because it was considered unsafe and at risk of collapse.

Officials requested multiple alarms and focused on exterior firefighting efforts while shutting down nearby Naito Parkway.

The blaze also spread to nearby vegetation, trees, and rooftops, creating additional smaller fires around the building, KATU 2 has reported.

Authorities have not determined the cause of the fire or whether anyone was inside the vacant warehouse.