The collapse happened just before 7:00 a.m. on the 700 block of S. 15th Street.
The workers were on scaffolding when the 3-story brick building collapsed. Police said a 40-year-old man suffered head, neck and back injuries and was hospitalized in serious condition.
Two other workers, ages 28 and 41, were being treated at a hospital for minor injuries. The same building suffered a partial collapse last Wednesday. The Red Cross is currently helping the tenants of the apartment building.
Information from The Associated Press was used in this article.