6 © Containment of Underground Nuclear Explosions from an underground test could go unde- tected. 3. Are we running out of room to test at the Test Site? Efforts to conserve space for testing in Rainier Mesa have created the impression that there is a ‘‘real estate problem’’ at the test site.® The concern is that a shortage of space would result in unsafe testing practices. Althoughit is true that space is now used economically to preserve the most convenient locations, other less convenient locations are available within the test site. Suitable areas within thetest site offer enough space to continue testing at presentrates for several more decades. 4. Do any unannouncedtests release radioac- tive material? A test will be preannouncedin the afternoon 2 days before the test if it is determinedthat the maximum possible yield of the explosion is such that it could result in perceptible ground motion in Las Vegas. An announcementwill be made after a test if there is a prompt release of radioactive material, or if any late-time release results in radioactivity being detected offthe test site. The Environmental Protection Agency is dependent on the Department of Energy for notification of any late-time releases within the boundaries of the test site. However, if EPA is not notified, the release will still be detected by EPA’s monitoring system once radioactive material reachesoutsidethetestsite. If it is judged that a late-time release of radioactive material will not be detected outside the boundaries of the test site, the test may (and often does) remain unannounced. OVERALL EVALUATION Every nuclear test is designed to be contained and is reviewed for containment.’ In each step of the test procedure there is built-in redundancy and conservatism. Every attempt is made to keep the chance of containment failure as remote as possible. This conservatism and redundancy is essential, however; because no matter how perfect the process may be, it operates in an imperfect setting. For eachtest, the containment analysis is based on samples, estimates, and models that can only simplify and (at best) approximate the real complexities of the Earth. Asa result, predictions about containment depend largely on judgments developed from past experience. Most of what is known to cause problems—carbonate material, water, faults, scarps, clays, etc.—was learned through experience. To withstand the consequences of a possible surprise, redundancyand conservatism is a requirement not an extravagance. Consequently, all efforts undertaken to ensure a safe testing program are necessary, and must continue to be vigorously pursued. The question of whetherthe testing program is ‘‘safe enough’’ will ultimately remain a value judgmentthat weighs the importanceoftesting against the risk to health and environment. In this sense, concern about safety will continue, largely fueled by concern about the nuclear testing program itself. However, given the continuanceof testing and the acceptance of the associated environmental damage, the question of‘adequate safety’’ becomes replaced with the less subjective question of whether any improvements can be made to reduce the chances of an accidental release. In this regard, no areas for improvement have been identified. This is not to say that future improvements will not be made as experience increases, but only that essentially all suggestions that increase the safety margin have been implemented. The safeguards built into each test make the chances of an accidental release of radioactive material as remote as possible. See for example: William J. Broad, ‘‘Bomb Tests: Technology Advances Against Backdrop of Wide Debate,’’ New York Times. Apr 15. 1986, pp. C1-C3. 7See ch. 3 for a detailed accounting of the review process.