The Atlas Powder Company was incorporated in Delaware on October 18, 1912 as part of the court-ordered breakup of the explosives monopoly of E.I. du Pont de Nemours & Company. As part of the settlement, parts of DuPont's black powder and dynamite business were spun off to two new companies, the Hercules Powder Company, capitalized at $13 million, and the Atlas Powder Company, capitalized at $6 million. Atlas functioned as an independent explosives and chemicals company until July 21, 1971, when it was purchased by Imperial Chemical Industries Limited (U.K.) and became its American affiliate under the name ICI Americas Inc.

Atlas began business on Jan. 1, 1913, with four former DuPont black powder plants at Ooltewah, Tenn., Belleville, Ill., Pittsburg, Kan., and Patterson, Okla., and three ex-DuPont dynamite plants at Landing, N.J., Senter, Mich., and Webb City, Mo. Later that year, it purchased the Reynolds Works near Tamaqua, Pa. from the Potts Powder Company,where it manufactured electric exploders, blasting caps, nitric and sulphuric acids, dynamite, and blasting detonators. In 1915, Atlas purchased The Giant Powder Company, Consolidated, which held the first U.S. rights to the Nobel dynamite patents, giving it a presence on the West Coast.

Following the lead of DuPont and Hercules, Atlas began diversifying from explosives into other chemical lines with the 1917 acquisition of Richards & Co., Inc., of Connecticut, and its sales subsidiaries Zapon Leather Cloth Company and Celluloid Zapon Company, manufacturers of lacquers and artificial leather. In 1925, the Pacific Lacquer & Bronze Company was added to the Zapon family. In 1921, Atlas contracted with the Darco Corporation to build an activated carbon plant in Marshall, Tex., and in 1928 Richards & Co., Inc., purchased the Duratex Corporation, a manufacturer of pyroxylin and rubber coated fabrics which also brought a controlling interest in Darco. Atlas bought the assets of the Brevolite Lacquer Company of North Chicago in 1933 and combined it with the Midwest business to the Zapon Company as the Zapon-Brevolite Lacquer Company. Traditional explosives capacity increased with the 1932 purchase of the Peerless-Union Explosives Company. The Atlas Research Laboratory was established at the Reynolds Plant in 1930, and Atlas de Mexico, S.A., was organized as a sales company in 1937.

Atlas devoted all of its plants to military needs during World War II and operated three ordnance plants under contract from the government. However, despite a second surge during the Korean War, the post-World War II years brought a major restructuring. The Duratex line of coated fabrics and plastics was discontinued in 1948, and the Zapon-Darco industrial finishes business was sold in 1955. The following year, Atlas bought the Thermaflow Chemical Corporation of Pennsylvania, makers of high-impact reinforced plastic molding compounds, and the Aquaness Corporation of Houston, Texas, a maker of chemical compounds used in the petroleum industry. In 1959, Atlas formed Solar Nitrogen Chemicals, Inc., as a joint venture with the Standard Oil Company (Ohio) to manufacture ammonia fertilizers. At the same time, explosives plants were being closed. As a consequence, Atlas changed its name to Atlas Chemical Industries, Inc., on May 31, 1961, and the next day completed a merger with The Stuart Company, a Pasadena pharmaceuticals maker. In 1997, after numerous spinoffs and restructurings, the pharmaceuticals business of Atlas became AstraZeneca LP, which has its headquarters in the former Atlas facilities in the Wilmington suburbs.