SAN JOSE (CBS SF) — One person was injured and two homes heavily damaged late Wednesday night when a 2-alarm fire erupted in a backyard RV and quickly spread to the houses, forcing 15 residents to flee to safety.

The San Jose Fire Department said crews responded to 911 calls reporting the fire behind a home in the Horace Mann neighborhood on 7th St. at around 11:43 p.m.

Arriving firefighters discovered massive flames engulfing the backyard from the blaze that had started in an RV. The fire was quickly spreading to a two-story residence and a single-story home.

A male victim was treated at the scene and taken to a local hospital. His condition was not known early Thursday.

San Jose Fire Department Public Information Manager Erica Ray said the blaze was under control at about 12:20 a.m., but not before both buildings were heavily damaged.

Approximately 15 people, including 3 children, were displaced from the two homes. The American Red Cross has been dispatched to assist them.

What caused the RV to burst into flames was still under investigation.