Bunker-busting bombs are pretty darned effective against hardened underground bunkers, but maybe it's not such a good idea to blow up chemical or biological weapons (that may just spread 'em, which makes things worse).
So the Pentagon dreamed up something straight out of science fiction movies: a rocket ball!
The Pentagon has a new secret weapon to neutralize sites containing
chemical or biological weapons: rocket balls. These are hollow spheres, made of rubberized rocket fuel; when ignited, they propel themselves around at random at high speed, bouncing off the walls and breaking through doors, turning the entire building into an inferno. The makers call them "kinetic fireball incendiaries."
David Hambling of Wired's Danger Room blog has more: http://blog.wired.com/defense/2008/11/secret-rocket-b.html