It happened at a PG&E training facility at 9:54 a.m., according to PG&E.
Police say two people were on board and sustained injuries. Both victims were taken to the hospital.
PG&E says the contractor helicopter, a Bell 407, was performing training when the crash occurred.
Firefighters say one person was inside the helicopter and had to use tools to get the person out.
The Federal Aviation Administration and National Transportation Safety Board will investigate the crash.