A Pennsylvania bill, which took seven years to pass, ensures that nurses and other caregivers will not be forced to work double shifts, a common practice at hospitals and other facilities that can be dangerous for nurses and patients alike. According to a 2004 University of Pennsylvania study, the risk of medical error was as much as three times higher when a nurse worked a shift of 12 1/2 hours or longer. In 2005, a report published by the Pennsylvania Department of Health showed that 13.6% of the state's registered nurses had experienced mandatory overtime in the two weeks prior to taking the department's survey.