William M. Hackman, 83, who since the 1960s had owned Orange Hill Farm in Middleburg, which became his base for breeding thoroughbred racehorses, died of lung cancer Feb. 27 at his winter home in Fort Lauderdale, Fla. He lived in Middleburg.

In 1966, he bought 75 thoroughbreds -- 25 broodmares, 10 foals, 14 yearlings and 26 horses in training -- from the British Lord Astor's Cliveden Stud. Those horses became the foundation of the Orange Hill line, which became a leading consigner at the Saratoga and Keeneland select summer yearling sales.

Notable stakes winners from the Orange Hill line included the fillies Sinking Spring, Silk Hat II, Lucy Manet and Schematic.

Mr. Hackman was a 1939 graduate of Franklin & Marshall College in his native Pennsylvania, where he funded scholarships and underwrote the refurbishing of classrooms and laboratories. He served on the school's board of directors from 1972 to 1986.

During World War II, he worked on the Manhattan Project, which built the atomic bomb, and for the War Production Board. After the war, he entered the chemical business, founding Hatco Chemical Co. in Fords, N.J., in 1950. He worked in plastics and received several patents before selling his company in 1960.

His marriage to Eileen Hackman ended in divorce. His second wife, Lucille M. Hackman, died in 2001.

Survivors include a son by his first marriage, James M. Hackman of Middleburg; a brother; and a granddaughter.