ARCADIA - Four homes were damaged Monday in the 100 block of West Norman Avenue in a fire started by a downed power line that ignited either grass or a palm tree, said a Monrovia fire official.
The 1:36 p.m. fire was initially reported as a grass fire, which spread to four homes within 300 to 400 feet of each other on Norman, said Monrovia Fire Department Battalion Chief Dave Cruz.
He said units from Pasadena, South Pasadena, Monrovia, Monterey Park, Alhambra and Los Angeles County joined Arcadia units in responding to the fire. It took them about 75 minutes to control the blaze, he said.

The homes were already in flames when firefighters arrived at the scene. Three were doused and the one was still burning an hour later, fire officials said.

The cause of the fire was under investigation, but there were reports a power line may have ignited a tree, which fell onto the roofs of the homes, authorities said.

Cruz said all the homes had roof damage either to the house or garage areas and one home suffered extensive damage after a portion of its roof collapsed.

He said a Pasadena firefighter sustained an injured knee fighting the fire and was treated at the scene and taken to a local hospital.

The extent and dollar amount of the damage was not immediately known.