The couple’s home has been inspected by Hazmat teams from Orange County Public Health. The kitchen floor has been ripped out and the walls and nearby bathroom have been sanitized. The home is inhabitable until construction can be done to restore the kitchen and all the appliances.

The rocks, described as a smooth orange colored one and a smaller green one, have been sent to a state lab for testing. Initial tests at the county health department revealed phosphate. Chemistry experts said the rocks may have been coated with phosphorous, a substance that can spontaneously ignite when exposed to oxygen.

Meanwhile officials from the U.S. Department of the Navy and from Camp Pendleton say they don’t believe the substance stems from any military training exercises. The San Onofre Nuclear Generating Station is believed to not play a role in the source of the burning rocks, experts said on Thursday.