Diamond Shamrock, Incorporated

Diamond Shamrock was one of the major oil refining and marketing companies in Texas back in 1993. It has more than 6000 employees and over $ 2.5 billion in revenue. The origin of Diamond Shamrock can be traced back to three companies: Diamond Alkali, Shamrock Oil and Gas, and Sigmor Corporation.

There was a group of glass manufacturers who founded Diamond Alkali in Pittsburgh, Pennsylvania in 1910 to produce soda ash, which is an important component in the glass industry. A large industrial plant was built at Painesville, Ohio in 1912.In the 1920s, under the leadership of T.R. Evans, Diamond Alkali developed into a significant chemical company. It, then, expanded into the production of calcium carbonates, coke, cement, chlorine, and an array of different products.

Under the presidency of T.R. Evans' son, Ray Evans, the company moved to decentralize after World War II. In 1946, in Deer Park, Houston, Texas, the construction on a new plant was started to produce chlorine and caustic soda. Diamond Alkali changed its headquarters from Pittsburgh to Cleveland, Ohio in 1948. A third plant was built in Muscle Shoals, Alabama in the 1950s and Diamond Alkali further extended its range o products into plastic and agricultural chemicals.

In the 1960, the company successfully opened another facility in Delaware City, Delaware and purchased several additional chemical companies including the Chemical Process Company of Redwood City, California and Nopco Chemical Company of New Jersey. Despite its growth, Diamond Alkali feared absorption by a larger chemical firm or by one of the major conglomerates. Eventually in 1967, it emerged with Shamrock Oil and Gas of Amarillo to increase its corporate strength.

The second progenitor of Diamond Shamrock, the Shamrock Oil and Gas, was founded on August 9th 1929, by John Sheerin, who named the company for a symbol of his native land. The company headquartered in Amarillo and financed by Fownes family of Pennsylvania. During the mid 1940s, Shamrock Oil and Gas became a major producer of natural gas.

In 1967, Shamrock Oil and Gas and Diamond Alkali merged to form the Diamond Shamrock Corporation. At the time of the merger, the products of the company were about 20 % oil and gas and 80 % chemical. Later on, the company expanded its oil and gas exploration efforts in the early 1970s and built quite a few new chemical plants, including the Battleground plant in Houston. In 1978, the company headquarters were moved to Dallas. That very same year, Sigmor purchased its station back from Diamond Shamrock, yet it continued to market Shamrock Diamond products.

In 1987, the Diamond Shamrock Refining and Marketing Company separated from Diamond Shamrock Corporation, the parent company, and became an independent company headquartered in San Antonio. As part of the reorganization, Diamond Shamrock Corporation changed its name to Maxus Energy Corporation and served all legal ties to Diamond Shamrock Refining and Marketing- now simply known as Diamond Shamrock, Incorporated.