The Ottawa River flows through the economic hub of western central Ohio: Allen County. Allen County and the surrounding area that makes up the Ottawa River watershed has a diverse economy made up of agribusiness, manufacturing, healthcare, education, retail, and professional services. The Cenovus Lima Refinery is the oldest continuous operating refinery in the U.S. and produces approximately 25 percent of all gasoline consumed in Ohio. The Lima P&G plant is the largest liquid detergent bottling plant in the world. The General Dynamics JSMC in Lima is the only U.S. Army battle tank production facility in the U.S. Throughout its history, the Ottawa River has tolerated the pressures of economic, industrial and population expanse. The Ottawa River struggled with issues common to other small rivers flowing through highly developed and industrial areas. In 1972, the federal Clean Water Act set forth water pollution control standards that have made dramatic impacts on water quality across the nation. In response, this region collectively has invested and made improvements throughout the watershed drastically improving the health of the Ottawa River.