ATP Oil & Gas Corporation (NASDAQ: ATPG) today announced that it has resumed production at the ATP Titan platform which services the company’s Telemark Hub. Production from the ATP Titan, shut-in since May 14, resumed after the operator of the Mars pipeline temporarily shut in the pipeline to allow for the tie-in of a new offsetting platform which has now been completed. Production at the ATP Titan is proceeding as expected and will ramp up over the next few days. ATP also announced that it has completed perforation at the lower B sand at the Mississippi Canyon (MC) 941 A-2 well, part of the Telemark Hub, and operations to frac-pac have commenced. Work on the MC 941 A-2 well is expected to be completed before the end of June, 2012 and the well will be placed on production immediately. The MC 941 Block produces through the ATP Titan floating drilling and production platform. ATP operates the ATP Titan and Telemark Hub which is in approximately 4,000 feet of water with a 100% working interest and holds a 100% ownership in ATP Titan LLC which owns the ATP Titan and associated pipelines and infrastructure. About ATP Oil & Gas Corporation ATP Oil & Gas is an international offshore oil and gas development and production company with operations in the Gulf of Mexico, Mediterranean Sea and the North Sea. The company trades publicly as ATPG on the NASDAQ Global Select Market. For more information about ATP Oil & Gas Corporation, visit www.atpog.com. Forward-looking Statements Certain statements included in this news release contain "forward-looking statements" within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934. ATP cautions that assumptions, expectations, projections, intentions, plans, beliefs or similar expressions used to identify forward-looking statements about future events may, and often do, vary from actual results and the differences can be material from those expressed or implied in such forward looking statements. Some of the key factors which could cause actual results to vary from those ATP expects include, without limitation, volatility in commodity prices for crude oil and natural gas, the condition of the capital markets generally, as well as ability to access them, the timing of planned capital expenditures, uncertainties in estimating reserves and forecasting production results, operational factors affecting the commencement or maintenance of producing wells, and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments affecting its business. ATP assumes no obligation and expressly disclaims any duty to update the information contained herein except as required by law. While ATP does not file reports with the SEC containing probable and possible reserve quantities, ATP occasionally will include them in news releases, presentations and discuss such reserves publicly. ATP and its independent third party reservoir engineers use the term “probable” to describe volumes of reserves potentially recoverable through additional drilling or recovery techniques that, by their nature, are more speculative than estimates of proved reserves. Any estimates of reserves in this news release have been prepared by our independent third party engineers. More information about the risks and uncertainties relating to ATP's forward-looking statements is found in the company's SEC filings or website, www.atpog.com.