WASHINGTON (AP) — The Biden administration has reversed a decades-old decision to revoke the security clearance of Robert Oppenheimer, the physicist called the father of the atomic bomb for his leading role in World War II’s Manhattan Project.

U.S. Energy Secretary Jennifer Granholm said the 1954 decision by the Atomic Energy Commission was made using a “flawed process” that violated the commission’s own regulations.

“As time has passed, more evidence has come to light of the bias and unfairness of the process that Dr. Oppenheimer was subjected to while the evidence of his loyalty and love of country have only been further affirmed,” Granholm said in a statement on Friday.

Oppenheimer, who died in 1967, led the Manhattan Project, which developed the atomic bombs dropped on Hiroshima and Nagasaki