On December 9, it was first announced that the Minnesota Department of Health was investigating a foodborne illness outbreak among people who had attended two events held at the Greysolon Ballroom in Duluth, Minnesota. The outbreak was caused by norovirus. Approximately 250 people attended the first event and 100 people attended the second event. The food was served by Greysolon Ballroom by Blackwoods. Multiple ill employees were identified. It was suspected that ready-to-eat food had been contaminated by an infected food worker.