Firefighters in San Luis Obispo County battled two structure fires on July 4, one in San Luis Obispo and another in Cayucos.

At about 7:30 a.m., San Luis Obispo city firefighters responded to reports of a fire on the roof of a commercial building on the 800 block of Capitolio Way. Investigators quickly determined, because of remnants of pyrotechnics found on the roof, that fireworks sparked the blaze.

Firefighters quickly extinguished the fire. An investigation is ongoing.

At about 6 p.m., a caller reported a motor home on fire in rural Cayucos. Cal fire crews arrived to find the vehicle on the 400 block of Old Creek Road fully engulfed in flames.

Investigators have not yet determined the cause of the Cayucos fire.