Mix, 50, was charged with two counts of obstruction of justice, each punishable by 20 years in prison and a $250,000 fine.
U.S. Magistrate Judge Daniel Knowles accepted the plea, but ordered that the defendant restrict his travel to Texas, Louisiana, Massachusetts and New York, according to Bloomberg. He was arrested last month.
A grand jury indictment accuses Mix of deleting electronic messages to a supervisor and a contractor so as to prevent them from being used in a federal investigation of the oil spill.
Court documents stated that Mix was a drilling and completions project engineer for BP. Following the Deepwater Horizon rig's uncontrolled blowout and explosion on April 20, 2010, Mix worked to get an estimate of the amount of oil leaking from the well. He was also a part of efforts to stop the leak. The incident killed 11 men on board the rig and spurred the largest environmental disaster in U.S. history, the Justice Department said.
BP reportedly sent several notices to Mix requiring that he keep all information, including his text messages. However, the allegations are that on or about Oct. 4 that year, Mix allegedly deleted a string of more than 200 text messages with a BP supervisor from his iPhone.
Prosecutors said this was done after Mix learned that his electronic files were to be collected by someone working for BP's lawyers.
Some of the deleted texts were recovered and contained sensitive internal BP information, showing that certain procedures to stop the oil flow were failing.
In one of the messages Mix allegedly wrote, Too much flowrate - over 15,000. The criminal charges against Mix were the first filed in the investigation of the blowout of BP's Macondo well.