Fire officials expect a 500 acre wildfire in Mariposa County to be contained tonight. They say the fire is no longer a threat. The blaze, which authorities say was started when sparks flew on some dry grass as a man used a grinder, broke out around 11 a.m. yesterday.

About 25 homes were threatened for some time.

Firefighters are using water-dumping helicopters and planes to contain the blaze. At least 16 fire engines are on the scene.

Smoke from the blaze could be clearly seen here in Tuolumne County.