Containers (10) for the storage of red blood cell (RBC) compositions (22) are disclosed. The container walls (12) are made of a plastic composition that includes a polymeric material and at least one extractable agent that includes a terephthalate ester in an amount effective to suppress hemolysis in red blood cells. A preferred composition includes polyvinyl chloride (PVC) and di-2-ethyl hexyl terephtalate (DEHT). The composition may include approximately 20-45% by weight terephtalate ester, such as DEHT.