LONGMONT, Colo. (CBS4) — Firefighters put out a blaze at an abandoned sugar mill on the southeast side of Longmont early Monday morning.

And not for the first time.

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The same mill caught fire in September of 2016.

(credit: Boulder County Sheriff’s Office)

Monday, fire crews were alerted to the fire just before 3 a.m.

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A portion of the building was “fully involved” when crews arrived, according to a news release from the Boulder County Sheriff’s Office.

An aerial attack on the fire prevented it from spreading to other parts of the property.

Local streets were expected to be closed for five hours.

The exact cause of the fire is under investigation.

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