San Luis Obispo County firefighters helped Monterey County put out a grass fire near San Miguel early Monday afternoon, according to Cal Fire.

The 70-acre blaze broke out about 12:40 p.m. at Ranchita Canyon and Cross Canyon roads. It was contained within an hour by crews from the two counties working together.

San Luis Obispo County sent two crews, two bulldozers, five fire engines and a tanker. Nobody was hurt, and no structures were threatened.

Capt. Jennifer Valdez of San Benito-Monterey Cal Fire said the blaze began when a farmer disking his field struck a rock, causing a spark that ignited grass.