UPDATE 1-Alberta regulator issues orders against Plains Midstream Canada
February 26, 2013 at 15:03 PM EST
CALGARY, Alberta, Feb 26 (Reuters) - Alberta's Energy Resources Conservation Board, which regulates pipelines in the province, issued four "high-risk enforcement actions" on Tuesday against Plains All American Pipeline LP's Canadian unit as it wrapped up an investigation into one of the province's largest-ever oil spills.