NEWARK, Del. (CBS) — Four people, including a firefighter, were injured in an apartment fire in Delaware early Friday morning.

The fire started at about 4 a.m. at the Salem Village Apartments on Oakdale Road in Newark.

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When firefighters arrived, they encountered heavy smoke and flames billowing from the apartment building.

The fire quickly went to a second alarm, bringing several Fire Companies to the scene to assist. The fire was placed under control in about an hour.

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The Delaware State Fire Marshal’s Office said a firefighter and three residents were injured and were taken to Christiana Hospital for treatment.

Fire officials said damage to the building is extensive.

The cause of the fire remains under investigation.

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