In 1914 in Columbus, Ohio, Fletcher Heath and Beman Dawes started the Ohio Cities Gas Co., which built its first oil refinery in West Virginia. In 1926, six years after the name of the company was changed to Pure Oil, its headquarters were moved to Chicago. From their offices in the Pure Oil building, company executives oversaw oil wells and refineries located in Ohio, West Virginia, Oklahoma, and Texas. A new research laboratory opened in 1950 in suburban Crystal Lake; eventually, Pure Oil operated a refinery at Lemont, Illinois. The company's annual sales grew from about $80 million in the late 1920s to over $700 million by the early 1960s, when it ranked among the 100 largest industrial corporations in the United States and employed more than 1,000 people in the Chicago area. In 1965, Pure Oil was purchased by the Union Oil Co. of California. As late as the mid-1970s, about 2,200 Chicago-area residents were employed by Union Oil.

This entry is part of the Encyclopedia's Dictionary of Leading Chicago Businesses (1820-2000) that was prepared by Mark R. Wilson, with additional contributions from Stephen R. Porter and Janice L. Reiff.