Cryonics procedures can only begin after legal death, and cryonics "patients" are considered legally dead. Cryonics procedures ideally begin within minutes of cardiac arrest,[7] and use cryoprotectants to prevent ice formation during cryopreservation.[8] The first corpse to be cryopreserved was that of Dr. James Bedford in 1967.[9] As of 2014, about 250 bodies were cryopreserved in the United States, and 1,500 people had made arrangements for cryopreservation after their legal death.[10]