Owners of an oil pipeline that burst in California this week must take numerous corrective measures, including an in-depth analysis of factors contributing to the spill and a plan to fix any flaws found, before they can restart the line, U.S. safety officials said on Friday. The corrective action order issued on Thursday by the U.S. Transportation Department's Pipeline and Hazardous Materials Administration, or PHMSA, is not regarded as a disciplinary enforcement sanction against the company, Plains All American Pipeline LP , officials said.