Three families found themselves displaced Wednesday following a fire that caused some $250,000 in damage at a two-story, 12-unit residential building in El Cajon, authorities said.Two people suffered minor smoke inhalation in the fire, which was reported just before 9 p.m. Tuesday at 1077 E. Lexington Ave., said El Cajon Fire spokeswoman Monica Zech. The blaze was knocked down within 15 minutes, she said.Two occupants of an apartment next to the one where the fire broke out were rescued from their balcony by firefighters using a ladder truck. They were treated at the scene for minor smoke inhalation, Zech said. No other injuries were reported.One apartment was seriously damaged by fire, two units had fire and smoke damage, and two or three others sustained water damage, Zech said. Total damage was estimated at $250,000.The American Red Cross was assisting the three displaced families, Zech said.The cause of the fire was not immediately apparent and an investigation was under way.