Marines Investigate Burning Rock Source

As a San Clemente woman heals from third-degree burns inflicted by mysterious beach rocks that ignited in her pocket, the Marine Corps has entered the investigation to figure out what happened.

“We’ve already intiated an internal investigation to determine the possible origins of the rocks,” said Camp Pendleton spokesman Capt. Barry Edwards. "We’re going to conduct a thorough investigation.”

No timetable has been set for finishing the study. The rocks were found to contain combustible phosphorus, but their source remains a mystery.

Officials from the San Diego Department of Environmental Health said their counterparts in Orange County thoroughly investigated the area of San Onofre Beach where the woman found the rocks, which ignited in her pants after she returned to her north San Clemente home.

Investigators with the county determined the beach was safe.

“We don’t have any plans to investigate further based on everything that the Orange County people found," said Gig Conaughton, spokesman for the San Diego County Department of Environmental Health. “They already canvassed the area trying to find anything else and they haven’t.”

For now, it's still unclear why the rocks burst into flame.

“At this point, it’s still something of a mystery,” Conaughton continued. “There’s no evidence to indicate a source.”

Phosphorus is used in several ways in munitions. San Onofre State Beach is leased from land owned by the Marine base, and San Clemente Island off the coast is a live fire range for the Navy.

The Orange County Register reported that the woman and her husband (who burned his hand trying to help her) are healing well after skin grafts.