Abstract: The present specification describes a process by which a blood substitute (hereinafter referred to as "HemoSafe") is derived from uniformly stabilized monomers and polymers of deoxyhemoglobin in its tight (T) conformation, with oxygen affinity similar to that of human blood. Two classes of HemoSafe are derived respectively from animal-hemoglobin and humanhemoglobin. HemoSafe (animal) differs from HemoSafe (human) in that it is free of polymers in order to reduce potential immunogenicity if used in man. Both types of HemoSafe may be derived in the following manner. The stabilized deoxyhemoglobins are converted to their carbonmonoxy derivatives (CO-HemoSafe) which are then stable under pasteurization conditions to render them viral disease transmission-free. CO-HemoSafes are stable for 2 months at 56.degree. C. in either the solution or the freeze-dried state. For transfusion CO-HemoSafes are easily oxygenated under sterile conditions by photoconversion yielding oxy-HemoSafe.