Officials said Sunday that a five-alarm fire that ripped through an ambulance depot in Freeport was not considered suspicious.

The massive fire broke out Saturday at an ambulance service building on Commercial Street and left a shell of structures and damages. Video captured plumes of black smoke billowing into the air.

Officials said four first responders were injured, two of which were Freeport firefighters, and one was a Northwell medic. All four were treated with smoke inhalation and later released from the hospital. A third firefighter was treated at the scene for a minor facial injury.

The Nassau Fire Marshal's Office confirmed to News 12 Long Island that the fire started in one of the ambulances and spread to others.

Oxygen cylinders stored in the building and some acetylene tanks that are used for repairs further fueled the fire.

The fire damaged about 20 ambulances.

The Freeport Fire Department told News 12 Long Island the fire marshal turned the investigation over to the Department of Environmental Conservation, which will discuss with the building owner if an environmental assessment is needed and what the cleanup process should involve. Officials said this is typical protocol.

Freeport resident Calvin General expressed concern about the chemicals that were in the plumes of smoke and if they could have any impact on health. News 12 Long Island reached out to the DEC but did not hear back.

The ambulance company is not a 911 service. It is used as a transportation service for patients. The Freeport Fire Department said the fire will not have an impact on emergency ambulance services in the area.