RARITAN TOWNSHIP - Authorities say they're investigating a house fire in New Jersey that severely burned a man and left five firefighters injured.

Hunterdon County prosecutors say first responders were notified of the Raritan Township blaze around 5:30 p.m. Sunday.

Authorities say a man has been airlifted to a Livingston hospital. His condition is not known.

Raritan Fire Chief Steven Wetter tells NJ.com a firefighter suffered smoke inhalation. Another had debris in his eye and three had elevated blood pressure levels.

Wetter says the fire spread rapidly due to the age and lack of fireproofing in the home. The building was extensively damaged.

The newspaper says property records show sections of the wooden house date to 1700.

The cause remains under investigation.