OBJECTIVES: I. Define toxicity and the maximum tolerated dose of humanized monoclonal antibody A33 (MOAB A33) when combined with carmustine, fluorouracil, vincristine, and streptozocin in patients with advanced colorectal cancer. II. Determine the effect of chemotherapy on human antihuman antibody response and on the pharmacokinetics of humanized MOAB A33 in these patients. III. Define the humanized MOAB A33 dose for a phase II study.