Now in October 1949, Oppenheimer and the GAC recommended against the development of the Super. He and the other GAC members were motivated partly by ethical concerns, feeling that such a weapon could only be strategically used, resulting in millions of deaths: "Its use therefore carries much further than the atomic bomb itself the policy of exterminating civilian populations." They also had practical qualms, as there was no workable design for a hydrogen bomb at the time. Regarding the possibility of the Soviet Union developing a thermonuclear weapon, the GAC felt that the United States could have an adequate stockpile of atomic weapons to retaliate against any thermonuclear attack. In that connection, Oppenheimer and the others were concerned about the opportunity costs that would be incurred if nuclear reactors were diverted from materials needed for atom bomb production to the materials such as tritium needed for a thermonuclear weapon.