The American Red Cross, which controls about 45% of the nation's blood supply, does not currently accept donations from people with known hemochromatosis. Everyone agrees that the blood is safe and of high quality. There is no risk of passing on a genetic disease through blood transfusions. But the Red Cross has a long-standing policy that potential donors are not allowed to receive direct compensation for their donation (beyond the usual orange juice and cookie). Because people with hemochromatosis would otherwise have to pay for their therapeutic phlebotomies, they would in effect be getting something of value for being able to donate for free. Thus the Red Cross has ruled that such donations violate their policy.
FDA regulations do permit hemochromotosis patients to donate blood, but with some special restrictions on how the blood is marked and how the blood banks operate. As a consequence, few blood blanks in the US currently accept blood from people with hemochromatosis, and most of the blood they give as a result of therapeutic phlebotomy is discarded. (People with hemochromatosis who wish to donate blood should check to see if any blood banks in their area will accept their donations.) This is not true in other countries, which have generally removed any restrictions on this blood.
The American Medical Association and many other groups have advocated for removal of restrictions for the acceptance of blood donations from people with hemochromatosis.
Source: American Diabetes Association