 Best known for their Valvoline Oil products, Ashland Oil relocated to Covington, Kentucky in 1999, merged with Marathon Oil, and sold its remaining petroleum shares to Marathon in 2005, dissolving their petroleum division.The original oil refinery, located in Catlettsburg, is still in operation today and is currently owned by Marathon Petroleum Corporation.Calgon Carbon constructed the Big Sandy Plant in 1961 and it has since became the world's largest producer of granular activated carbon.