Unexploded Ordnance: Hidden Danger on Military Bases

As post-Cold War military downsizing that began in the 1980s continues with new rounds of congressionally mandated U.S. base closures, the U.S. Department of Defense (DoD) faces a long-term liability problem: unexploded ordnance (UXO). Concerns about possible soil and groundwater contamination from munitions residues, such as explosives and lead, and the dangers from disturbing or mishandling munitions that were fired but failed to detonate have hampered the DoD's efforts to transfer closed military bases to the public as required by law. Although DoD spent nearly $7 billion cleaning up former installations, many sites are not suitable for reuse, and the military has had difficulty finding buyers or even transferees willing to take the land for free. Jacqueline MacDonald, an engineer at RAND, recently wrote an article, "Cleaning Up Unexploded Ordnance," in Environmental Science and Technology about the risks involved with and potential solutions to the problem of UXO.

The presence of UXO is inevitable on any land used for military training or weapons development and testing. Types of UXO, such as small arms ammunition, mortars, and tank-fired projectiles, can vary widely, and each munition type poses different challenges for detection and clearance. The traditional method for clearing UXO is called "mag and flag". This involves surveying the range with a hand-held metal detector and placing a flag at the center of anomalous signals. Flagged areas are later excavated to search for UXO. Mag and flag has numerous problems, such as a high false alarm rate, and the sluggishness of the process.

MacDonald examined recent research on better UXO detection and clearance methods. Two basic types of metal detectors are used for finding UXO: magnetometers, which measure distortions in the Earth's magnetic field, and electromagnetic induction (EMI) devices, which create an electric current underground induces a magnetic field, which in turn can be used to locate metal objects. MacDonald concluded that the greatest potential for near-term improvements lies in developing signal-processing algorithms that allow EMI devices and magnetometers to correlate the strength, frequency, or decay rate of signals from the detectors with known patterns for different types of UXO.

Another issue complicating the cleanup of UXO is the lack of certainty over what cleanup process and standards ultimately will be required for UXO sites. Negotiations between the Environmental Protection Agency (EPA) and the DoD have raised questions about which agency should have final say in the steps to be taken for UXO clearance. This makes further progress on the issue extremely difficult.

MacDonald argues that as Congress and the Bush administration consider policies for managing military land, the UXO issue should not be overlooked. Decisions to transfer more military land back to the public should consider whether continued attempts to reuse UXO-contaminated land for nonmilitary purposes make sense, or whether this land should remain under military oversight in perpetuity or at least until better detection and clearance technologies are available. Clear guidance from Congress and the Bush administration is needed to resolve UXO problems at military ranges already transferred or slated for transfer, particularly with regard to which agency has regulatory authority over these problems, and the end goals for UXO clearance need to be specified.

For more information: Order the RAND Reprint of "Cleaning Up Unexploded Ordnance"