Police, fire and hazmat teams were called to UPMC Mercy around 9 a.m. after a suspicious package was found in a Mercy Pavilion office.
Police say an employee who opened a letter called 911 after discovering a powdery substance inside.
In a statement, UPMC tells KDKA Radio the substance was tested and determined to be flour.
Normal operations have resumed at the hospital.
Out of an abundance of caution, one person was examined before the substance was determined to be flour.