POTENTIAL FOR A RISK-BASED APPROACH
TO UXO RESPONSE
In the absence of sifting each UXO site to a depth of at least several feet, complete elimination of UXO can never be guaranteed. This is because technologies for detecting UXO are imperfect: no existing technology can provide complete assurance that every buried UXO item has been located and removed. Sifting all the soil may be feasible in a limited number of cases, but usually it will not be possible because of either cost constraints or concerns about irreparable damage to ecosystems and threatened and endangered species. Each alternative other than sifting will leave some level of residual risk. A credible and technically sound risk assessment process is essential for evaluating these residual risks and for choosing the best among imperfect choices for UXO detection and clearance.
This chapter first explains the basis for and history of risk assessment. It then describes how risk assessment could be used to improve management of UXO sites and explains why risk assessment has not yet played a major role at UXO sites. The final section establishes a set of criteria that a credible UXO risk assessment method should meet.
The problem of assessing risks from UXO sites is not unique. Throughout history, humans have had to make difficult choices about managing risks in the face of technical, information, and resource limitations. Risk assessment has evolved as a discipline to meet this need. There is a wealth of knowledge about risk assessment to draw from in informing choices about UXO sites. Although the use of risk assessment at UXO sites has been questioned, we be-