Beach rocks that sparked fire had high level of phosphorus

SAN CLEMENTE, Calif.

Lyn Hiner suffered second and third degree burns. She needed surgery after the rocks she collected along San Onofre State Beach last month ignited when she got home.

The land is owned by the United States Marine Corps and operated by state park rangers. The rocks were located in San Diego County.

Phosphorous is normally stored in water, but when it's out of water and exposed to oxygen, it can spontaneously burst into flames.

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