Having first specialized in heavy chemicals such as sulfuric acid, in 1904 Grasselli Chemical had introduced the production of zinc as spelter. By 1928 Grasselli Chemical, a vertically integrated enterprise, manufactured heavy chemicals, fertilizer, black scrap, zinc, and explosives with plants in 22 cities; owned zinc ore and pyrite deposits as well as coal deposits; and employed between 3,700 and 4,500 workers. Despite its size, Grasselli remained a family enterprise with the Grassellis and their in-laws serving as officers and dominating the board of directors.

Chemical manufacturers shared certain patterns in the decades before World War I. Owing to limited economies of scale, Grasselli Chemical expanded by adding more plants rather than by increasing the size of plants. Also, it integrated forward, replacing its sales agents with direct selling, and grew more by internal expansion than by merger.

Grasselli Chemical had gradually drifted into manufacturing explosives. It sold mixed acids for the production of nitroglycerine in the late 1860s and early 1870s. Since Grasselli supplied superior acids for the manufacture of dynamite, an explosives firm built a dynamite factory in Cleveland to take advantage of Grasselli Chemical as a supplier. The Grassellis improved the product by suggesting the substitution of nitrate of soda for the saltpeter. In 1900 E.I. du Pont de Nemours & Co. and the Grasselli Chemical Company jointly organized a company to supply nitroglycerine. Finally, in 1917 a Grasselli subsidiary acquired and consolidated three explosives companies.

World War I affected Grasselli Chemical in an unanticipated way; the United States Government confiscated German patents, selling them to American interests through the Alien Property Custodian. This gave Grasselli Chemical the chance to become a producer of drugs and intermediates, broadening its product line. The Alien Property Custodian sold Bayer dye and drug patents to Grasselli Chemical, which transferred the medicinals to Sterling Products, and sold patents to Sterling Products, which resold them to Grasselli Chemical. However, Grasselli Chemical later sold out its coal-tar chemicals facility.

From the 15th century onward the Grassellis were chemists, druggists, perfumers, and the like at Torno on Lake Como in northern Italy. When Napoleon Bonaparte made this Po valley region a part of France, Giovanni Angelo Grasselli saw an opportunity. With another Italian emigrant he became a manufacturing chemist in Strasbourg in northeastern France. He built his first chemical plant there about 1800 and a second in 1810 at Mannheim in western Germany.

His son, Eugene Ramiro Grasselli (1810-1882), was born in Strasbourg, studied chemistry at the Universities of Strasbourg and Heidelberg, and worked with his father. Emigrating in 1836, he apprenticed in Philadelphia, Pennsylvania. In 1839 he started a chemical business, selling sulfuric acid, a good proxy for economic development, and other mineral acids to the meatpacking industry in Cincinnati, Ohio, known then as "Porkopolis." In response to his competitors, and to be nearer oil refining customers who wanted to integrate backwards by producing their own sulfuric acid, he opened a second factory in Cleveland, Ohio, in 1867 and also relocated the main office as well as his family there.

The new chemical works, on the Cuyahoga River, virtually adjoined the Rockefeller refinery; as Standard Oil prospered, so did the Grasselli firm. In that year Caesar Grasselli participated in Cleveland sulfur price-fixing; in 1872 the Cleveland oil refiners tried to depress the sulfuric acid price but the parties compromised. His partnership, doing business as Eugene Grasselli & Son (1873-1883), diversified in the late 1870s, manufacturing higher value-added products.

Under C.A.'s leadership the company continued to prosper as a private concern. In the year following his death, Grasselli Chemical embarked on a new direction; it obtained a listing on the New York Stock Exchange, becoming a publicly held corporation. Then came a bigger change. Later that year (1929) Grasselli Chemical was acquired by du Pont in the largest merger in which one of the top 200 nonfinancial companies acquired a company not on the list. Du Pont exchanged stock valued at $73 million for the Grasselli stock, 26 plants, and assets of $56 million. Thus the third-generation heirs of an Italian immigrant entrepreneur ended the independent family enterprise; such family enterprises typically do not endure beyond the third generation.

For additional information on Caesar and other Grassellis see William Haynes, Chemical Pioneers (1970 reprint of 1939), and David Van Tassel and John J. Grabowski, eds., Encyclopedia of Cleveland History (1987).