Firefighters battled three alarm fire at Mountain View High School

Firefighters battled flames at Mountain View High School in El Monte this morning.

The county fire department had about 150 firefighters fighting the fire, until about 6:31 a.m.

#MountainviewIC #LACoFD Battalion10 units call knockdown 6:31am twitter.com/LACoFDPIO/stat…

— LACounty Fire PIO (@LACoFDPIO) January 21, 2013

Fire inspector Tony Imbrenda told our media partner NBC4 it started at about 2:30 this morning.

#MountainviewIC #LACoFD Battalion10 units continuing to pour water on fire twitter.com/LACoFDPIO/stat…

— LACounty Fire PIO (@LACoFDPIO) January 21, 2013One firefighter suffered a minor back injury, but wasn't taken to the hospital.  The cause of the fire is under investigation.

Because of conditions, the firefighters took a defensive position, Imbrenda said just before 6:30 a.m.

"We have a number of companies set-up around the perimeter of the structure, and we’re continuing to pour a lot of heavy water in to knock down the hot spots and get to the fire and areas and void spaces in the building where it’s continuing to burn," he said.

School is not in session today in honor of the Martin Luther King, Jr. holiday.