This may be the source for some of the new NYT information... although not speculation on why it was covered up or political effects: http://rosatom.ru/en/pres

This may be the source for some of the new NYT information... although not speculation on why it was covered up or political effects: http://rosatom.ru/en/press-centre/news/nuclear-scientists-are-setting-up-a-commission-to-find-out-ruthenium-106-source-of-origin-/ http://rosatom.ru/en/press-centre/news/nuclear-scientists-ar... tl;dr likely to be a transportation spill from a reprocessing plant based on the specificity of the element.