HOUSTON, March 8 (Reuters) - The U.S. Coast Guard on

Friday were trying to identify the source of an oil spill off

the coast of Huntington beach, California, the agency said.

The sheen, estimated at 2.5 miles (4 km) in length and 0.5

miles (800 meters) in width, was discovered after a Coast Guard

helicopter flew over the site at sunrise.

The spill is located roughly 2.8 miles (4.5 km) off

Huntington Beach, near two oil drilling platforms but it was

unclear whether either were the source of the spill, according

to the Coast Guard's statement.

Beta Offshore, a subsidiary of Amplify Energy Corp ( AMPY ), reported

a potential spill of produced water from its offshore Platform

Elly off Huntington beach on Friday, according to a regulatory

filing, causing the company to shutdown a pipeline.

It was unclear whether that incident was related to the

large oil sheen spotted by the Coast Guard on Friday.

"At this time, we have no indication that this sheen is

related to our operations", Amplify Energy Core said in a

statement.