MONTEREY, Calif. (AP) — Nearly 5 million gallons of sewage spilled into the ocean on California's Central Coast after a filter at a water treatment plant got clogged and the computer system failed to sound an alarm, an official said Monday, forcing several popular beaches to close. The spill at the facility in the city of Marina started Friday night and an operator stopped it about eight hours later on Saturday morning, Monterey One Water general manager Paul Sciuto said. "A number of alarms did not get to the operator because of a computer communications' failure, but we still don't know what caused it," he said. Environmental health officials closed at least seven beaches, many with silvery sands or rocky outcrops that offer beautiful vistas and are busy with surfers, dog walkers and picnickers. They sit in a peninsula that includes the towns of Pebble Beach, Monterey and Carmel, which attract tourists and golfers from around the world. Among the most popular is Lovers Point, a wedding spot that is also used for fishing, swimming and water sports. Shawn Johnson, director of veterinary science at the Marine Mammal Center in Sausalito, said young mammals are at greatest risk from the raw sewage, but harbor seals won't give birth in the area until May. The area also is home to sea otters. "We're keeping an eye out for any marine mammals that might be affected by this spill, and at this point, we haven't recovered or rescued any," he said. Lab samples were taken Sunday to determine if the area about 110 miles (160 kilometers) south of San Francisco is safe, and results are expected Monday, Sciuto said. If it rains in the area, Monterey County said it will send an advisory for all area beaches, advising people not to have contact with ocean water for three days after a storm even if lab results come back negative for contaminants. ___ Information from: The Monterey County Herald, http://www.montereyherald.com