Arthur M. Mackwell, 85, a Washington representative for environmental issues for Engelhard Industries, a New Jersey company that manufactures catalytic converters, died of dementia Feb. 20 at the Washington Home hospice.

His daughter, Sally Bauer, confirmed the death.

Mr. Mackwell began his career with Engelhard in 1968 and retired about 30 years ago. Catalytic converters control air pollution in automobiles.

Arthur Mulford Mackwell was born in Nutley, N.J., and served in the Navy during the late 1940s.

He was a 1952 graduate of Rutgers University in New Jersey, where he then became a print and radio journalist. He also worked on the campaign and speechwriting staffs of New Jersey Govs. Robert B. Meyner and and Richard J. Hughes, both Democrats. In 1964, he came to Washington as press secretary for Sen. Harrison A. Williams Jr. (D-N.J.)

Mr. Mackwell was a past board member of the nonprofit environmental organization American Rivers and a past board chairman of the Cacapon and Lost Rivers Land Trust in West Virginia.

He was board president of the Ontario housing cooperative in Washington, where he lived.

His first marriage, to Alice Degenaars, ended in divorce.

Survivors include his wife of 43 years, U.S. District Court Senior Judge Gladys Kessler of Washington; five children from his first marriage, Steven T. Mackwell of Hawley, Pa., Sharon A. Mackwell of New Haven, Conn., and Merida, Mexico, Sally M. Bauer of Downingtown, Pa., Arthur D. Mackwell of St. Petersburg Beach, Fla., and Clark S. Mackwell of Sarasota, Fla.; five grandchildren; and four great-grandchildren.

— Bart Barnes