(Portland, OR)  --  One person is recovering from minor injuries following a two-alarm fire at a historic building downtown.  Firefighters were called to the commercial building near Southwest 11th Avenue and Alder Street yesterday morning on reports of a fire on the roof.  Fire officials say some workers were installing roofing material and using a propane torch to dry out the roof deck when the flame ignited some solvent-based primer on the roof.  One worker suffered burns to his hands.  Officials have not yet released an estimate of the damage to the building.