However, none of the residents were injured.
The Fire Service had three trucks at the scene, two involved in the extrication of two injured people from the car, including the male driver who was trapped with a fractured leg.
The other Fire Service crew focused on the gas emergency.
St John Ambulance Service Heretaunga territory manager Brendon Hutchinson said four people were taken to hospital - two aged in their 20s, one aged 17 and the other aged 12.
All were reported early last night by Hawke's Bay DHB to be in stable condition.
Police at the scene said they believed speed was a significant factor in the cause of the crash, and it was possible the car and another vehicle had been racing just before the crash.
Housing New Zealand contractor Prestige yesterday boarded up the damaged front entrance of the unit where the crash happened.