On December 23, 1997, the Portland region of the American Red Cross (ARC) notified the Oregon Health Division about a cluster of adverse ocular reactions among six patients who had received out-patient red blood cell (RBC) transfusions at a hospital in Washington; all patients experienced severe bilateral conjunctival erythema within 24 hours of transfusion. Since the initial report, 106 similar reactions in 74 patients in 14 states (Alabama, California, Connecticut, Maine, Michigan, Minnesota, Montana, Oklahoma, Oregon, Pennsylvania, Texas, Utah, Washington, and Wisconsin) have been identified. This report summarizes the preliminary findings from three of these states about the ongoing investigation of these reactions.