PATIENT CHARACTERISTICS: Age: 12 and over Performance status: Zubrod 0-2 Life expectancy: At least 2 years Hematopoietic: See Disease Characteristics Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) (unless due to Gilbert's disease or direct CLL infiltration of liver) SGOT or SGPT no greater than 2.5 times ULN (unless due to direct CLL infiltration of liver) No hepatic disease that would preclude study Renal: Creatinine no greater than 1.5 times ULN OR Creatinine clearance at least 60 mL/min Cardiovascular: No unstable angina pectoris No cardiac arrhythmia No prior grade III or IV New York Heart Association cardiac problem No cardiovascular disease that would preclude study Other: No prior grand mal seizures (infantile febrile seizures allowed) No other active malignancy No other uncontrolled concurrent medical problem No active uncontrolled infection No prior hypersensitivity to arsenic trioxide or related drugs No neurologic, endocrine, or other systemic disease that would preclude study No other condition that would preclude study compliance Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception