They say three children were playing with fire in the backyard, when due to the windy conditions, flames got out of control.
The kids were released to their parents, according to the Contra Costa County Fire Protection District.
SKY7 was over the scene shortly after the fire started around 1:30 p.m. on Cambark Court, off Arthur Road.
Aerial views of explosive 2-alarm fire in Martinez
Several explosions sounded as crews fought the flames.
Wind gusts of more than 20 mph hour hampered firefighting efforts and whipped the flames, which destroyed cars on the property and the base of a tower with high-tension power lines.
Fire officials say crews will stay on scene to keep an eye out on any flare-ups.