HUNTINGTON BEACH, Calif. (CNS) — A “sheen” possibly connected with a boat that sank was spotted in the ocean off the coast of Huntington Beach Friday, prompting lifeguards to clear the water and beaches while an investigation was conducted.

The sheen was reported late Friday morning near the Huntington Beach Pier. City spokeswoman Jennifer Carey said it’s unclear if the substance is oil.

The city fire department dispatched a hazardous materials team to the scene, and the U.S. Coast Guard also responded, Carey said.

People were being urged to avoid the water and beach between Seapoint Street and Beach Boulevard while crews investigated the source of the sheen.

According to the Coast Guard, the sheen was possibly related to a 42- foot vessel that sank near Bolsa Chica State Beach on Thursday night. No injuries were reported in connection with that incident, the USCG reported.

Crews were working to ensure that environment protocols were being followed, the USCG reported.