OUTLINE: Patients are stratified into 1 of 8 categories: first relapse no greater than 6 months after complete response vs second relapse or refractory vs prior hematologic disorder vs myeloid blast crisis of chronic myeloid leukemia vs lymphoid leukemia vs lymphoma vs myeloma vs myelodysplasia. Patients receive IV arsenic trioxide over 2-3 hours for 5 consecutive days with 2 days of rest. Treatment continues in the absence of disease progression until complete response or 90 days is reached. Upon achieving complete response, treatment is discontinued for 30 days. Patients exhibiting complete response receive a second 28 day course of consolidation therapy while in remission starting no sooner than 31 days after the end of induction therapy. Patients are followed monthly.