NEWPORT BEACH—A mile-long stretch of beach in Newport Beach was closed this morning due to a sewage spill.

The spill of approximately 1,000 gallons “was caused by an operator error during routine maintenance of a sewer main line” and closed the beach between Bayside Drive Beach and China Cove, according to a statement Monday evening from the OC Health Care Agency.

The affected bay water area will remain closed until results of follow-up water quality monitoring meet acceptable standards, the agency said.