The process of disarming the world of its thousands of surplus nuclear missiles has thrown up a new and dangerous environmental problem for the Russian communities who live near Soviet-era military rocket sites. The liquid fuel used by Soviet era missiles and rockets -unsymmetrical dimethylhydrazine (UDMH) is both highly toxic and hard to eradicate from the environment once leaded, warns Dr Lev Fedorov of Russia's Union for Chemical Safety.