LOVELAND, Colo. -- Firefighters in Larimer County spent Friday afternoon battling a grass fire that was burning about three miles east of Carter Lake, just west of Loveland.

The fire started at 11:05 a.m. when a private landowner was building a road in the area and struck a rock, 7NEWS reported. He tried to put the fire out but couldn't, so he called authorities.

The fire is about 25 acres and 70 percent contained, a Berthoud Fire spokeswoman said.

No structures were lost, and no injuries were reported. A few homes were voluntarily evacuated as a precaution.

The homeowner who sparked the fire will not be charged, 7NEWS reported.

Fire crews from Lyons, Loveland, Johnstown, Mountain View, and Hygiene and Larimer County sheriff emergency services were all at the scene. A small single-engine air tanker attacked the fire throughout the day.