By Janene Scully

A brush fire burning Sunday off Highway 166 east of the Santa Maria Valley has closed the roadway, according to emergency dispatch reports.

At approximately 1:30 p.m., personnel from Los Padres National Forest, Santa Barbara  County Fire Department and Cal Fire responded to the blaze north of Highway 166 at Rock Front Ranch.

The blaze, dubbed the Front Fire, had ballooned to 300 acres, Andrew Madsen, Forest Service spokesman, said at 3:30 p.m.

“We’ve initiated a full response, including air tankers,” Madsen said.

By 4:30 p.m., the fire had burned more than 600 acres with zero containment.

Sounds of air tankers and other aerial firefighting tools could be heard over Santa Maria on Sunday afternoon.

Authorities were discussing whether to close Highway 166 due to the fire and equipment in the area, but the highway initially remained open.

However, as the fire crept closer to the busy two-lane roadway, authorities closed Highway 166 between Highways 101 and 33 just before 5:30 p.m.

Highway 166 links the Central Coast to the southern San Joaquin Valley and sees heavy traffic at the start and end of weekends. An alternative route is Highway 46 in Paso Robles.

Due to the location of the fire, Los Padres National Forest personnel were managing the incident.

More than 150 firefighters were involved in the battle Sunday afternoon, according to Forest Service information.

The cause of the fire remained under investigation, authorities said.

Noozhawk North County editor Janene Scully can be reached at jscully@noozhawk.com.