Seven residents were displaced by a kitchen fire at the Opportunity Center in Palo Alto on Saturday evening that resulted in significant water damage, a fire official said. Crews responded to the 88-unit affordable housing complex, located at 33 Encina Ave., around 5:30 p.m. where a fire was reported on a second-floor unit, Deputy Fire Chief Catherine Capriles said. Sprinkler heads extinguished the fire by the time crews were at the scene and residents had already evacuated, she said. The fire was caused by unattended cooking oil on a hot plate, according to Capriles. Residents in the involved unit and others below were displaced by the blaze, which left a significant amount of water damage, she said. The American Red Cross was called to assist seven people. The fire left an estimated $50,000 to $60,000 in damage, Capriles said. No injuries were reported.