The Bikini Atoll in the Marshall islands is one of the most polluted places in the pacific ocean. The US military conducted nuclear testing around there and simply swept the pollution in one place. There are dozens of reports of cancer from both former military personnel an nearby local population. And concerns are rising with elevated sea level that pollution will be leaking at greater pace then currently.
These are just two examples of the US military neglecting safety concerns with their nuclear technology. There is no single spectacular event like the Chernobyl disaster. But rather decades of neglect and disregard to public safety which polluted many areas leaving potentially an overall damage on par—and potentially greater—then the Chernobyl disaster.