The DIAMOND SHAMROCK CORP. began as a Cleveland-based chemical company which, in 2003, was headquartered in Dallas under the name Maxus Energy Corp. The Diamond Alkali Corp., a forerunner of Diamond Shamrock, was incorporated in Delaware in 1929 as the successor to a company of the same name that was incorporated in West Virginia in 1910. Founded by a group of investors with ties to glass manufacturing, Diamond Alkali was established to facilitate the production of soda ash, an important material for the manufacture of glass. In 1911, Raymond Evans (one of the founders) chose Painesville as the site of its main chemical plant. The combination of local salt deposits, an abundant water supply from Lake Erie, and the area's accessibility to lake freighters carrying Michigan limestone and railroads hauling West Virginia coal made Painesville an ideal choice for the company's operations. In the 1920s, Diamond Alkali diversified its production facilities to include the manufacture and maketing of a large number of basic inorganic and organic chemical products, such as soda ash, caustic ash, laundry soda, soda crystal, bichromates, cement, chlorine, alkalis, and coke. A pioneer in the development of alkali-based products, the company found that new products often produced side effects, which subsequently resulted in the development of still more products. By the mid-1960s, the company's line had grown to over 1,400 products. Diamond was a major employer in the area, and the economy of many surrounding communities was directly tied to its fortunes.
In 1928, just three years after Raymond F. Evans became president of the company, Diamond moved its corporate headquarters from Pittsburgh to the UNION COMMERCE BLDG. in Cleveland. It was under Evan's leadership that the firm became one of the largest chemical, oil, and gas companies in the United States. After the Second World War, the firm expanded by opening plants in Houston, TX, Muscle Shoals, AL, and Delaware City, DE. In addition, the company expanded its range of products to include plastics like polyvinyl chloride and chemicals for the agricultural industry. After acquiring several of its competitors in the chemical industry, Diamond Alkali merged with Shamrock Oil & Gas Corp. in 1967, creating the Diamond Shamrock Corp. After the merger, the company moved its headquarters from the Union Commerce Bldg. to the new office tower at Superior and E. 13th St. At the time of the merger, Diamond Shamrock's chemical operations made up about 80 percent of the company's business, with oil and gas making up the remaining 20 percent. Soon after the merger, however, company executives repositioned the company's emphasis away from its industrial chemicals business and toward its oil enterprises by expanding oil and gas exploration. After William H. Bricker became CEO in 1976, Diamond Shamrock closed its plant in Painesville, where it had operated for 65 years. In 1979, Diamond Shamrock moved its corporate headquarters to Dallas, where the company's name was changed to Maxus Energy Corp. in 1987 and its refining and marketing business became a separate entity called the Diamond Shamrock Refining and Marketing Company (later shortened to Diamond Shamrock in 1990). The loss of Diamond Shamrock was a major economic blow to Cleveland at the time as the only operation remaining in the area was a chemical research center in Painesville.
Despite their reduced presence in Cleveland, Maxus (and its former Diamond Shamrock past) soon returned to the public's attention in Northeast Ohio. In September 1979, the Cleveland Press ran a series of award-winning articles by investigative reporter, Peter Almond, revealing major environmental and health issues at the former Diamond Shamrock site. In the early 1990s, Federal and State environmental officials, reported the discovery of investigations that uncovered 750,000 tons of chromate materials, three waste lakes, and other toxic contaminants at an 1,100 acre site fomerly occupied by Diamond. Located on the border of Painesville Township and Fairport Harbor, environmental officials uncovered evidence of run-off into nearby Grand River and Lake Erie. Acting to halt the spread of still further pollution, officials from the Ohio Environmental Protection Agency brokered a deal with Maxus and several other companies with ties to the site to spend between $3 and $5 million to clean up the area. The clean-up effort shored-up existing barriers to contain the contaminants and, as early as 1998, local developers began searching for ways to redevelop the site for recreational uses.