Southern California Edison (SCE), a subsidiary of Edison International , said on Thursday that it was probing whether its equipment was associated with the ignition of two Los Angeles-area wildfires this year.

Contractors test soil samples for contaminants like lead or mercury and remove tainted soil. If a section still tests high, crews remove 3 to 6 more inches of soil and retest. The goals of soil testing are to leave a property safe for families, children and pets as well as protect groundwater, wildlife and air quality.