Vancouver firefighters late Tuesday night doused a duplex fire at 3900 Gibbons St., near Falk Road in the Bagley Downs neighborhood.Two women were treated for minor smoke inhalation and taken to a local hospital, said Capt. Scott Willis with the Vancouver Fire Department.Firefighters responded about 11:40 p.m. Tuesday. The first to arrive radioed that flames were visible but there was too much smoke to see exactly what was burning, according to emergency radio traffic monitored at The Columbian.Firefighters said it was a duplex and, five minutes later, that “all occupants are out of both residences.”A hydrant was nearby. After a backup safety crew was organized, firefighters went inside and said they found no one. Also, occupants of both units said no one was inside.Officials blocked traffic on Falk at Gibbons and Plomondon Street as they brought their engines and hoses to the blaze.Firefighters said just before midnight that it was under control. They then focused on finding and dousing areas where flames might have reached in the building.The fire is considered accidental, but the cause could not be determined, Willis said. A preliminary damage estimate came in at $20,000 to the building; there was no dollar damage estimate for the building’s contents. John Branton: 360-735-4513 or email@example.com.