A 43-year-old woman is undergoing surgery after two rocks that she collected at a South County beach ignited in the pocket of her shorts, officials from Orange County Fire Authority said.
The incident happened about 3:30 p.m. Saturday when the woman was standing in her kitchen after returning from an outing to Trestles Beach. She had been home for about an hour when the pocket of her cargo shorts caught fire, OCFA Capt. Marc Stone said.
The rocks, described as small, the size of a hamburger patty, smooth and orange and green in color, fell from the shorts onto the floor and continued to burn the wood floor and fill the house with smoke.
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A witness said the rocks were still smoking. OCFA hazardous materials unit was consulted. The rocks have been taken to Orange County Public Heath and are undergoing testing.
Hmm. Mysterious. My first guess would have been charcoal because they may have felt just warm on the outside but still be smoldering on the inside, enough to catch clothes on fire. But that might not explain the smoke. The smell of the smoke would have been valuable – wood, sulfur-odor or chemical smell. There is not enough information in this story. Important details are missing.
Add on: The more I look at white phosphorus, the more I think it may be reasonable. It is reactive with air only 10-15 degrees above room temperature (she had it in her pocket – warmed up) and is commonly used in munitions like grenades and for smoke screens. It does cause such burns as described. Could this have been military waste or unexploded fireworks that were washed up on shore and, when dried up, exposed to air and warmed, ignited? See the ATSDR sheet here.
If anyone hears a followup to this story, let us know.
UPDATE (18-May-2012): Phosphorous substance found.
The Orange County Health Care Agency examined the two rocks, and tests revealed a “phosphorous substance” on the rocks, which now have been sent to a state laboratory for further testing, said Tricia Landquist, an agency spokeswoman.
James Earthman, a professor of chemical engineering and material science at UC Irvine, had a few possibilities: The inorganic chemical could have come from a passing ship or from nearby Camp Pendleton. And the reason for the delayed combustion could be because the rocks were still wet and didn’t ignite until they were dry — and, he noted, we don’t know what else could have been in the woman’s pockets.
The white/grey looks like common limestone pieces you would find at the beach. The green? No clue. Yellow is the phosphorus substance.
The mystery remains. I do suspect, however, that it might be solved eventually. Stay tuned.
Note: The paper spells phosphorus incorrectly. It is NOT phosphorous.