‘Mystery Spill’ Fouls Ocean Off Bolsa Chica State Beach : Environment: A light sheen of diesel fuel taints a half-mile strip of water but breaks up before polluting the beach. Marine life is not affected.

A small diesel spill tainted a half-mile strip of ocean water Thursday morning but broke up before polluting the beach.

The light sheen, caused by an estimated 15 gallons of diesel fuel, was spotted by Shell Oil crews about three miles off Bolsa Chica State Beach shortly before 9 a.m. It broke into patches and evaporated within a few hours.

“It’s so light you can’t even skim it. This stuff naturally dissipates before it gets to shore,” said U.S. Coast Guard Lt. John Meehan.

Based on its color and consistency, officials said the spill was definitely not crude oil from a tanker or oil platform. Meehan called it one of countless “mystery spills” from passing vessels that are often spotted in the well-traveled waters between Long Beach and Huntington Beach.

“There’s no ship to be found. It’s a light diesel product, probably from a smaller commercial vessel--a fishing vessel or a smaller passenger vessel, something that uses a lighter product” than a tanker, Meehan said.

Shell Oil crews spotted the sheen while in a helicopter that travels to the company’s oil platforms off Huntington Beach.

Coast Guard investigators couldn’t find a trace of the fuel when they arrived in a vessel by midmorning, said Petty Officer Ernest Gonzales. Huntington Beach lifeguards were alerted, but beaches and marine life were not affected.

Gonzales said small fuel spills are spotted on a daily basis in the ocean off the Long Beach-Huntington Beach area, but ones so close to shore are more rare. Many are accidental, although sometimes ships intentionally dump their bilge water.

“A lot of times it’s an engine malfunction. It’s not usually done purposely,” Meehan said.

Sometimes, the responsible ship captain is caught, but more likely not. Anyone caught spilling petroleum products into the ocean without reporting it can face criminal charges under federal law. If the spill is reported, civil fines are possible.