A fire broke out in a building near the Smithsonian Museum of Natural History on Monday morning, sending smoke billowing around the National Mall (not to mention Twitter).

No injuries were reported, and the museum's collections were not damaged, according to fire department spokespeople.

The fire broke out in a heating and air conditioning building located near the museum. Washington, D.C., Deputy Fire Chief Kenneth Crosswhite told Agence France Presse that the fire started in some air conditioning equipment and spread to the building's insulation.

The fire started about 7:30 a.m., several hours before the museum opens to the public. The Washington Post reported that the museum opened on schedule at 10 a.m.

Monday morning rush hour was disrupted by the smoke as traffic was diverted around several nearby streets.

The cause of the fire is still under investigation.