W.R. Grace and Company is an American chemical conglomerate based in Columbia, Maryland. Grace is divided into three business segments—Grace Catalysts Technologies, Grace Materials Technologies, and Grace Construction Products. Grace is a specialty chemicals and materials company. It has more than 6,700 employees in nearly 40 countries, and annual sales of more than US $ 2.5 billion. The company's stock, listed in 1953, trades on the New York Stock Exchange.

W.R. Grace and Company was founded in 1854, in Peru, by William Russell Grace, who left Ireland due to the potato famine, and traveled to South America with his father and family. He went first to Peru to work as a ship's chandler for the firm of Bryce and Company, to the merchantmen harvesting guano (bird droppings), used as a fertilizer and gunpowder ingredient due to its high levels of phosphorus and nitrogen.

His brother Michael joined the business and in 1865 the company name was changed to Grace Brothers & Co. The company set up head office operations in New York City in 1865. Working in fertilizer and machinery, the company was formally chartered in 1872, and incorporated in 1895.

There are two accounts of the incorporation date of W.R. Grace & Co. According to a New York Times account the company was incorporated, as part of estate and successor planning, in 1895. The three brothers consolidated most of their holdings into a new private company, incorporated in West Virginia, called W.R. Grace & Company. The consolidation involved W.R. Grace & Co. of New York, Grace Brothers & Co. of Lima, Peru, Grace & Co. of Valparaiso Chile, William R. Grace & Co. of London, and J. W. Grace & Co of San Francisco.

According to its website, W.R. Grace & Co. was incorporated in Connecticut in 1899. The listed capital of $6 million did not include Grace Brothers & Co. Limited in London or its branches in San Francisco, Lima and Callao, Peru, nor in Valparaiso, Santiago, and Concepción, Chile.

J. Louis Schaefer, who joined the company as a boy, would play a key role in not only W.R. Grace & Company, in which he became a vice president, but also as president of Grace National Bank. Schaefer would be a co-executor of the estate of Michael Grace with William's son and corporate successor, Joseph P. Grace. J. Louis Schaefer died in 1927.

For most of its history, Grace's main business was cargo shipping. To get cargo from Peru to North America and Europe, including guano and sugar, and noticing the need for other goods to be traded, William Grace founded a shipping division. Grace Line began service in 1882, with ports of call between Peru and New York. Regular steamship service was established in 1893, with a subsidiary called the New York & Pacific Steamship Co., that operated under the British flag. Ships built outside the United States prior to 1905 were banned from US registry. US-flag service began in 1912 with the Atlantic and Pacific Steamship Company. The activities of both companies and the parent firm were consolidated into the Grace Steamship Company beginning in 1916. The firm originally specialized in traffic to the west coast of South America; then later expanded into the Caribbean.

In 1916, Grace acquired a controlling interest in the Pacific Mail Steamship Company. In 1921, Pacific received five 535 ft. President class ships from the United States Shipping Board for transpacific operation. In 1923, the US Shipping board decided to place the five ships up for bid and Dollar Shipping Company won the bid. With no large ships for the transpacific operations Grace sold the Pacific Mail, its registered name, and goodwill to Dollar. Now without a transpacific service, Grace did not need the six intercoastal freighters and sold them off to the American Hawaiian Line. At this time Grace formed a new entity, the Panama Mail Steamship Company, to operate the smaller ships that were formerly owned and used by the Pacific Mail in the Central American trade. These ships were not involved in the sale to Dollar.

On the death of William R. Grace in 1904, he was succeeded by William L. Sauders as company President followed by Joseph Peter Grace, Sr. (1872–1950) who became president in 1907. In 1938 the Colombian Line merged with Grace Line bringing an end to the Colombian Line. During World War II Grace Lines operated numerous transports for the U.S. War Shipping Administration.

J. Peter Grace, Jr. took over management of the company after his father suffered a stroke in 1945. After the war the Grace line operated 23 ships totaling 188,000 gross tons, and an additional 14 more on bareboat charters. In 1954 the company bought Davison Chemical Company (founded by William T. Davison as Davison, Kettlewell & Company in 1832), and the Dewey & Almy Chemical Company (founded in 1919 by Bradley Dewey and Charles Almy). In 1960 Grace Line, inspired by the pioneering efforts of Sea-Land Service, Matson Navigation, and Seatrain Lines, sought to begin containerizing its South American cargo operations by converting the conventional freighters Santa Eliana and Santa Leonor into fully cellular container ships. However, the effort was stymied by the opposition of longshoremen in New York and Venezuela and the ships were repeatedly laid up idle and were ultimately sold to the domestic container line Sea-Land Service in 1964. In 1963 Grace made a second attempt to containerize its South American trade when it ordered the four M-class combination passenger-cargo ships Santa Magdalaena, Santa Maria, Santa Mariana and Santa Mercedes with partial cellular holds, but they were no more successful as mixing conventional break-bulk cargo and containers in the same ship negated the operating economies that full containerization promised.

The company bought a 53% stake in Miller Brewing in 1966, for $36 million; Lorraine Mulberger sold the stake for religious reasons. It sold the Miller stake in 1969 to Philip Morris for $130 million, topping a deal with PepsiCo for $120 million. In 1969 Grace also exited the shipping business to concentrate on its chemical and diversification ventures. Grace Line was sold and merged into Prudential Line in 1970, which was renamed Prudential Grace Line, and was itself in turn taken over by Delta Lines in 1978, thereby extinguishing the name Grace in ocean shipping. In 1987, by siting a can sealing plant in Shanghai, Grace became the first wholly foreign-owned company to do business in The People's Republic of China.

In 1928, Grace and Pan American Airways jointly formed Pan American-Grace Airways known as Panagra, establishing the first air link between the North and South America, that began operation in 1929.

The company has its headquarters in Columbia, an unincorporated census-designated place in Howard County, Maryland. Although W.R. Grace commissioned the Grace Building in New York City, built in 1971, the company no longer has any offices at that location.

Previously the company had its headquarters in Boca Raton, Florida. Prior to its closing, the Boca Raton headquarters had about 130 employees. On January 27, 1999 it announced it was moving its administrative staff to the Columbia office and closing the Boca Raton headquarters. About 40 of the employees went to Columbia, and some employees went to Cambridge, Massachusetts. In 2014, the company emerged from a 13-year bankruptcy case stemming from asbestos claims, and immediately built a new 90,000sqft headquarters building on its 160-acre Columbia campus.

Subsidiaries and some of their products include:

W.R. Grace and Company has been involved in a number of controversial incidents of proven and alleged corporate crimes, including exposing workers and residents of an entire town to asbestos contamination in Libby and Troy, Montana, water contamination (the basis of the book and film A Civil Action) in Woburn, Massachusetts, and an Acton, Massachusetts, Superfund site.

While Grace no longer makes asbestos-related products, W.R. Grace and Company has faced more than 270,000 asbestos-related lawsuits, of which 150,000 have been settled or dismissed and 120,000 remain.

After asbestos injury claims unexpectedly nearly doubled in 2000, W.R. Grace & Company filed for bankruptcy protection in 2001. The United States Department of Justice alleged that Grace had transferred $4 to 5 billion to subsidiary companies that it had recently purchased, shortly before declaring bankruptcy. Justice Department attorneys alleged that this amounted to a fraudulent transfer of money in order to protect Grace from civil suits related to asbestos. The bankruptcy court ordered the companies to return nearly $1 billion to Grace, which will remain as part of the assets to consider in the bankruptcy hearings.

In 2005, the U.S. Department of Justice began criminal proceedings against W.R. Grace. On February 7, 2005, the department announced that a grand jury in Montana indicted W.R. Grace and seven current and former Grace executives for knowingly endangering residents of Libby, Montana, and concealing information about the health effects of its asbestos mining operations. According to the indictment, W.R. Grace and its executives, as far back as the 1970s, attempted to conceal information about the adverse health effects of the company’s vermiculite mining operations and distribution of vermiculite in the Libby, Montana, community. The defendants are also accused of obstructing the government’s cleanup efforts and wire fraud. To date, according to the indictment, approximately 1,200 residents of Libby area have been identified as suffering from some kind of asbestos-related abnormality.

The criminal trial began in February 2009 after years of pretrial proceedings which reached the United States Supreme Court. By the time the trial was set to begin, one of the defendants, Alan Stringer, had died of cancer. David Uhlmann, a former top environmental crimes prosecutor has been quoted as saying about W.R. Grace & Co.: "There's never been a case where so many people were sickened or killed by environmental crime." The W.R. Grace case long festered in the court system on a 10-count indictment including charges of wire fraud and obstruction of justice. W.R. Grace has voluntarily paid millions of dollars in medical bills for 900 Libby residents.

On Friday, May 8, 2009, W.R. Grace & Co. was acquitted of charges that it knowingly harmed the people of Libby, Montana. It was also acquitted of subsequently participating in any cover-up. Fred Festa, chairman, president and CEO said in a statement, "the company worked hard to keep the operations in compliance with the laws and standards of the day.

In 1995, the European Patent Office (EPO) granted a patent on an anti-fungal product derived from the neem tree to the United States Department of Agriculture and W. R. Grace. The Indian government challenged the patent when it was granted, claiming that the process for which the patent had been granted had been in use in India for more than 2,000 years. In 2000, the EPO ruled in India's favour, but W. R. Grace appealed, claiming that prior art about the product had never been published in a scientific journal. On 8 March 2005, that appeal was lost and the EPO revoked the Neem patent.