Santa Monica beach evacuated after suspicious ‘acidic substance' washes ashore (PHOTOS)

A “hazardous acidic substance in the water” off the shore of part of Santa Monica beach has forced Los Angeles authorities to partially evacuate the packed coastline.

Lifeguards rushed to clear the water and the Hollywood-famous pier, closing it off from block 1700 of Ocean Front Walk to Tower 15, north of the pier, LA County Lifeguard spokesman Ken Haskett told local reporters.

As beach-goers took snapshots at the scene, swimmers were urged to stay out of the water. For now the public is not allowed to enter the cordoned off area until the nature of the substance is determined, ABC local news, KABS, reports.

The mysterious substance possibly comes from an offshore boat and could be chemically treated sewage, said Petty Officer Marshall Anderson with the US Coast Guard who spoke with KATLA news station.

If the substance is proved to be sewage, it will eventually dissipate naturally, Anderson added.