(Portland, OR)  --  Environmental services workers at OHSU in Portland walked off the job Wednesday to demand better working conditions.  The union employees say they've experienced bullying by managers and staffing issues.  They delivered a list of demands to management with more than 50 signatures.  OHSU released a response saying they recognize the issues raised by the staff and look forward to working collaboratively to reach agreement on a new contract.  OHSU says they've been bargaining with the union since February and more mediation is planned.