If Lake commerce and the Grand River docks dominated the 19th Fairport century scene, it can be said that the Diamond Alkai / Diamond Shamrock Corporation story consumed the 20th century chapter of Fairport business history. The Diamond Alkali, a chemical company incorporated in West Virginia by a glass businessman named T.R. Evans from Pittsburgh, began in 1910. The Painesville-Fairport area was a perfect source to pool the resources needed for glass manufacture. Salt, limestone, coal and water could be effectively harnessed, economically assembled then successfully transported. The ability to make derivatives on site only added to the relevance of this Pennsylvania, Ohio, West Viriginia triad glass manufacturing site.
The "Diamond's' first plant was built on the site of the original Painesville Township Park in 1912. Production of soda ash started early that year and customer demand proved steady. Within three years capacity was increased to 800 tons daily. WWI became the 'boom' years and the 'Diamond' became a leading government supplier of caustic soda and bicarbonate of soda. By 1924-25 the plant had added calcium carbonates, Portland cement, coke, and magnesium oxide to its production list. Magnesium oxide production would later prove useful as a key element in the the production of WWII incendiary bombs. Later contributions by the 'Diamond' would include chlorowax, a resin used in flame retardent paints and plastics. Periclase was produced. It was a material used in refractories. Post WWII products included hydrochloric acids, paraffins, and ammonium bicarbonate. Carbon Tetrachloride and silicates remained at the core of the plant's production. Fairport's Diamond Alkali reach spanned 100 miles from Toledo to upstate New York. The plant became the focal point of this northeastern chemical corridor of the era. The Diamond's motto became " Chemicals You Can Live By." The plant now encompassed over 1660 acres. Docks, a company freighter and nearly 1300 employees were mainstays in this chapter of plant history.
1948 marked an important date in the plant history. The world headquarters moved from Pittsburgh to Cleveland. As the manufacturing landscape changed, the plant aggressively pursued a merger with Standard Oil and Gas. This occurred in 1967 and the company became known as The Diamond Shamrock Corporation. Events between 1972-75 changed the manufacturing landscape once again. eight plants of a similar nature to the Diamond closed. Raw production was giving way to new synthentics. Pollution and environmental issues arose. Ultramar was now the new name of the corporation and New Jersey became a secondary home. Fairport's Diamond Plant closed its doors in June 1976. An era dating back to 1912 had ended. In 2001, Valero Energy purchased the Ultramar Company.
Today the 'Diamond' is a memory. Remnants of the plant still exist. Portions of the docks lie under the surface of the Lake. The Bluffs where the plant once stood are now barren fields. Discussions about repurposing the property remain stalled. Artifacts and a detailed model of the plant are housed at the Fairport Harbor Lighthouse and Marine Museum. Former employees still reside in Fairport and meet occasionally. The 'Diamond' remains to this day firmly rooted in the village. Its storied history is a large patch in the bicentennial quilt that is Fairport.