The former Giant Mine is North America’s largest and most technically challenging arsenic contaminated site. During the operational phase of the mine, some 237,000 metric tons of arsenic trioxide dust were stored in underground vaults within the mine. An interim mine site remediation plan has been approved for a maximum of 100 years, subject to a number of pre-conditions and regulatory approvals. Among these conditions is the requirement for a research program to identify methods to permanently eliminate the risks posed by the arsenic trioxide dust. As a first step, the independent Giant Mine Oversight Board initiated a comprehensive review of potentially promising methods.