Investigators said the accident involved a mini-van carrying two women and two children.
All four were taken to the hospital; however one of the kids had to be airlifted.
The other vehicle was a white pickup truck-- the male driver was also taken to the hospital.
The truck crashed into a fence surrounding a PG&E substation.
A power pole was also damaged in the crash.
Fire investigators said power would be out for some residents as they made repairs.