An employee was sweeping flour dust off of equipment when the machine guard unlatched and opened the machine guard door. The employee was attempting to close the door when another piece of the machine guarding became unsecured. While attempting to reinstall the guard that became unsecured, the employee's hand contacted the exposed motor chain, which was running. This caused the employee's hand to be pulled into the in-running chain and sprocket, partially amputating the employee's left pinky finger and lacerating three fingers.