Jack D. Lackner, 40, an employe of the Department of Energy and a former employe of the Environmental Protection Agency, died Nov. 19 at the Camelot Hall nursing home in Arlington. He had pneumonia and had been hospitalized or in a nursing home since Feb. 1, when he was injured in a bus accident.

D.C. police said the accident occurred when Mr. Lackner was struck by a Metro bus as he was crossing the street at 12 Street and Pennsylvania Avenue, SW.

Mr. Lackner, who lived in Arlington, was born in Los Angeles. He graduated from California State College in Los Angeles with a degree in civil engineering. He earned a master's degree in water resources management at the University of Wisconsin in 1967.

He spent the next two years as a Ford Foundation Fellow in Latin America. He moved to the Washington area in 1969 and as a staff member of the National Water Commission. In 1971, he conducted a study in water resources for the Commonwealth of Puerto Rico.

Mr. Lackner joined the EPA here in 1972. In 1975, he received an Outstanding Employe Award and was named management division director of the agency's Boston regional office. In 1978, he returned here and joined the Energy Department.

He was a member of Tau Beta Pi, an honorary engineering society, the American Water Resources Association and the American Society of Civil Engineers.

Survivors include his wife, Nancy L. Lackner, and two sons, Mark and Andrew, all of Arlington; his father and stepmother, Mr. and Mrs. Woodrow Lackner of Laguna Beach, Calif.; his mother, Margie Saylor of Toledo, Ore., and two brothers, William Lackner of Newport, Ore., and Michael Lackner of Los Angeles.