Editor’s note: Check back later Friday for an interview with the woman who was burned after collecting rocks at the beach.

SAN CLEMENTE – Two rocks that spontaneously ignited in a San Clemente woman’s shorts are being sent to a state lab for more testing, officials with Orange County Public Health said Thursday.

The two rocks, smooth and orange and green, were tested at the agency Monday after Lyn Hiner, 43, was severely burned Saturday an hour after she and her daughters collected seven rocks at Trestles beach.

The agency determined that a phosphate substance was on two rocks and that the other five had been cross-contaminated.

“The rocks are being sent to a state lab to verify our findings,” Tricia Lindquist, a spokeswoman with the healthcare agency said. “We have no clue what the phosphate is coming from. Since they were found at a state beach they will go to a state lab and from there it will be determined what state agency will look at them.”

Lindquist said it is expected to take at least two more weeks to test the rocks.

Trestles, where the rocks were first collected, is next to the San Onofre Nuclear Generating Station and the Camp Pendleton Marine base.

San Clemente Island, 59 miles off the coast of Trestles Beach, is owned and operated by various naval commands. The island has at least a dozen ranges there.

Capt. Barry Edwards, a spokesman at Camp Pendleton, said base officials and emergency personnel are standing by in case the county health agency needs assistance. Edwards said Base officials did get a query from the San Diego Hazardous Materials Incident Response Team about the burning rocks.

“There is no evidence that military training aids were involved in this,” Edwards said. “The base will cooperate with the investigation if asked.”

U.S. Navy Cmdr. Jason Salata, a spokesman for Naval Surface Forces, said the storage and handling of all naval weapons is taken seriously.

“We have rigorous accounting procedures,” he said.

Ken Shea, a professor who teaches organic chemistry at UCI, said the phosphorous found on the rocks is man-made and likely comes from munitions or flairs.

Shea said that phosphorous is normally stored in water.

“Only when it’s out of water and exposed to oxygen, it can spontaneously burst into flames,” he said.

Shea said the rock could have been slowly coated with a crust over time. That crust could have prevented the rocks from bursting into flames. When Hiner put the two rocks into her pocket with others, they could have been bumped or rubbed which could have caused the crust to rub off and them to suddenly ignite.

Shea said the incident is likely an isolated incident unless there is something big behind it.

He believes the San Onofre reactor would have had nothing to do with getting phosphorous into that area.

The incident was first reported to the Orange County fire Authority on Saturday at 3:33 p.m. when a 911 call reporting a ‘woman on fire in her home’ came into the Orange County Fire Authority.

Hiner was in her kitchen when her shorts suddenly burst into flames from the rocks in her right pocket. She tried to ‘stop, drop and roll’ but was unsuccessful in getting the flames out, Capt. Marc Stone said.

Her husband also tried to help and got second-degree burns when he tried to pull the shorts off, 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.

Firefighters responded immediately to the home on Avenida Estrella. When they arrived, the husband had successfully gotten the shorts off his wife and was hosing her down on the front deck with a garden hose, Stone said.

Paramedics treated Hiner for severe second- and third-degree burns on her right leg from her thigh to her knee and on her right arm, Stone said. The husband also was treated for second-degree burns on his arm.

Both were taken to Western Medical Center in Santa Ana. Firefighters took the rocks with them to show to doctors, Stone said. The rocks were still smoking while they were transported.

Hiner underwent surgery for the third degree burns Thursday.

Contact the writer: 949-454-7307 or eritchie@ocregister.com or twitter.com/lagunaini