Residents of an apartment building in Long Beach were evacuated and several hospitalized after a fire broke out Saturday.

Firefighters say the fire was contained to a third-floor apartment on Neptune Boulevard, however, smoke quickly spread throughout the building. A contractor working on the eighth floor heard residents stuck in the stairwell due to the thick smoke and brought them to safety.

All 150 apartments were evacuated and seven residents were taken to the hospital suffering from smoke inhalation. Officials say only one apartment had fire damage, but there is water and smoke damage to several others. The cause of the fire is under investigation.