BRIGHTON, Colo. (CBS4) – Investigators are trying to figure out how a fire that damaged multiple storage units overnight in Brighton started.

Someone was driving on Interstate 76 and saw flames near the Bromley Lane exit. After calling 911 just before 3 a.m., fire crews from Brighton Fire Rescue responded.

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(credit: Brighton Fire Rescue)

(credit: Brighton Fire Rescue)

Firefighters spent approximately 45 minutes battling the flames at the business, which was difficult in part because they had to cut into one of the locked units using a circular saw.

The effort by firefighters at the scene continued after daybreak.

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“They’re going to be working on hotspots for quite some time just because there is so much in those units. So it’s tough to fight this type of fire,” said Brighton Fire Rescue spokeswoman Natalie Ridderbos.

The property owner has been notified.

(credit: CBS)

(credit: CBS)

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That person will contact the owners of each storage unit and let them know how badly their unit and property may be damaged. No one was hurt but at least 20 units were damaged.