A brush fire on a Los Angeles hillside prompted a major emergency response Sunday.

More than 150 firefighters battled the 30-acre blaze on a steep chaparral-covered section of Mandeville Canyon above Brentwood and sent up a plume of smoke that was visible for miles.

Firefighters aided by water-dropping aircraft were able to contain 70 percent of the fire by late afternoon.

Investigators said a private company working on a road in the canyon had been using a weed whacker to clear brush around homes when its muffler overheated and sparked the fire.

LAFD Deputy Chief Trevor Richmond was asked to describe the severity of the fire on a scale of 1 to 10. He told the Los Angeles Times that it was about a 3, though the inferno was burning in “all directions.”

The five mile dead-end road through the canyon is home to some of Los Angeles' wealthiest residents and leads to side roads where the likes of former Gov. Arnold Schwarzenegger and Patriots quarterback Tom Brady have owned mansions.

In the desert east of Los Angeles, a 40-acre brush fire in the town of Mecca forced about 50 people to evacuate from an apartment complex.

Riverside County Fire officials said those residents were allowed to return after firefighters contained 50 percent of the blaze.

The Associated Press contributed to this report.