In this position, O'Leary won praise for declassifying old Department of Energy documents, including Cold War-era records that showed the U.S. government had used American citizens as guinea pigs in human radiation experiments, as had long been rumored. Clinton issued Executive Order 12891, which created the Advisory Committee on Human Radiation Experiments (ACHRE) to prevent such abuses of power. O'Leary also announced a $4.6million settlement payment to the families of victims of past radiation experiments. Other declassified documents included facts about plutonium the United States had left in South Vietnam.