HELENA - The Montana Department of Environmental Quality (DEQ) has signed an Administrative Order on Consent (AOC) with ExxonMobil Pipeline Company for investigation and cleanup of this past summer's Yellowstone River Oil Spill. "This document legally binds ExxonMobil Pipeline to conduct pollution monitoring, continued remediation and reclamation, and payment of penalties and costs to the state," said DEQ Director Richard Opper. A total of $1,060,390 has been transferred to DEQ by ExxonMobil Pipeline. That total includes past state cleanup costs of $760,390 and a cash penalty of $300,000. Additional penalty includes $1.3 million worth of DEQ-approved supplemental environmental projects to be completed by ExxonMobil. In addition, the AOC requires ExxonMobil to pay future state costs. To access the finalized AOC, work plan and other documents, please visit www.deq.mt.gov On the evening of July 1, 2011, an estimated 1,500, or 63,300 gallons of crude oil spilled into the Yellowstone River when the company's Silvertip Pipeline broke near Laurel. Exactly what caused the 12-inch pipeline to rupture is under investigation by the U.S. Pipeline and Hazardous Materials Safety Administration.