ACTON (CBS) — Fire crews have nearly contained a 100-acre brush fire is burning near Hubbard Road and Escondido Canyon Road in Acton.

About 200 county firefighters were called to the scene of the fire at 11 a.m. One out building was destroyed.

The blaze, which was threatening several homes, was fueled by extreme heat and five- to 10-mile-per-hour winds.

No injuries were reported and the cause of the fire is under investigation.

» PHOTOS: Brush Fire Burns In Acton