ARVADA, Colo. (CBS4)– Firefighters rushed to a burning office building on Saturday morning where heavy smoke was pouring from the roof. One person was rushed to the hospital with unknown injuries.

Firefighters rushed to the building at 64th and Wadsworth just before 10 a.m. where flames and heavy smoke was pouring from the building. It took crews several hours to get the fire extinguished.

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(credit: CBS)

(credit: CBS)

A neighbor described the large plumes of smoke and flames he saw coming from the building.

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“On fire, fire shooting out at least six feet in the air from the top where the firefighters were putting it out,” said neighbor Alice Leitch.

What caused the fire is being investigated.

Firefighters said the building is older and was not equipped with sprinklers.

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(credit: Arvada Fire Dept.)

(credit: Arvada Fire Dept.)