IMPERIAL BEACH, Calif. -- A sewage spill fouled a stretch of South Bay ocean coastline Monday, authorities said.

The overflow from a sanitation pipeline under Imperial Beach Fishing Pier was discovered Monday morning, according to the county Department of Environmental Health.

It was unclear when the problem began and how much effluent entered the surf.

Pollution warning signs will stand along the shore to the north and south of the pier until follow-up testing deems the area safe again for recreational uses, the DEH reported.