A fire starts in an outbuilding that houses the HVAC systems for the National Museum of Natural History. It is started by a contract worker who was welding in the building, which is located in the East side parking lot of the Museum. The fire causes a large cloud of smoke in the area around 10th Street, NW, and Constitution Avenue. There are no reports of injury or damages to the Museum but staff evacuates the building temporarily as a precaution and relocate to the Smithsonian Castle. Staff and students from the Smithsonian Early Enrichment Center relocate to the National Museum of American History. All return to the building at approximately 9:55 am. The Museum opens to the public at 10:10am. The incident also causes the National Mall to close between 7th and 12 Streets NW, temporarily.