After graduating from Amherst College, Haas earned a master’s degree in chemical engineering at MIT. Having enlisted in the Naval Reserves, he worked briefly for the chemical company his father had co-founded, Rohm and Haas, before being called to active duty in 1942. Discharged from the Navy in 1946, he returned to Rohm and Haas as a process engineer and, later, as an assistant plant manager in Knoxville, Tenn., and Houston, Texas. Although he met Chara Cooper, his future wife, at a dinner party in Houston, she, like him, was a native of the Philadelphia area.
According to his profile on the Rohm and Haas website, Haas felt that during his four years in the Navy, he had fallen behind on the rapid advances in the field of chemical engineering, so he moved into what he described as the “people side of the business.” In 1953, the year after he and Cooper married, he was named vice president of personnel at Rohm and Haas. In 1959, he became vice chairman of the board and in 1974 chairman.
Haas joined the MIT Corporation as a term member in 1965, and during two five-year terms, he chaired both the Chemistry and the Chemical Engineering Committees. He became a life member in 1975, and in 1987, one of his family trusts endowed the Haas Family Fellowship in the David H. Koch School of Chemical Engineering Practice. Two years later, he stepped down from active service to the Corporation, becoming a life member emeritus.
Throughout his life, Haas was a noted philanthropist. In 1960, when his father died, he began a 32-year tenure as chair of the charitable foundation — now the William Penn Foundation — that his parents had established in 1945. In 2009, when Dow Chemical bought Rohm and Haas for more than $15 billion, the family shifted $747 million to the Penn Foundation, as part of $1.25 billion in bequests to four charitable trusts.
Haas was also a major supporter of the United Way and the Boys and Girls Clubs, among other organizations. In 2009, he converted a 160-acre property that had been in his family since 1928 into a nature conservancy, the Brandywine Conservancy, augmenting the bequest with another 200-acre property he and his wife had bought in 1968.
After Haas’s death, Ed Rendell, the two-term governor of Pennsylvania, was quoted in the digital edition of The Philadelphia Inquirer as calling Haas “a gentle, extraordinarily decent and honorable man.” “If you met him for the first time, you would never have guessed he was extremely successful,” Rendell continued. “He didn't care much for the trappings of wealth or success. He only cared about using his resources to help others.” Indeed, according to the 5, Haas was known to his neighbors as “the spry old man who roamed the local roads picking up litter.”
In addition to his wife, Haas is survived by a daughter, Barbara; four sons, David, Leonard, Frederick and Duncan; and 10 grandchildren. A public memorial service is being planned.
Contributions in his memory may be made to the Boys and Girls Club of Philadelphia, attn. Development Dept., 1518 Walnut St., Suite 605, Philadelphia PA 19102, or to the United Way of Southeastern Pennsylvania, 1709 Benjamin Franklin Parkway, Philadelphia PA 19103.