Russian Rocket Explosion Releases Toxic Fuel Cloud  After a
Russian Proton-M rocket crashed in a fiery ball over the Kazakh
desert on Tuesday, plumes of black and orange smoke could be
seen hovering ominously over the crash site. The plume was
partly due to a highly toxic fuel, comprised of the chemical
compounds hydrazine and nitrogen tetroxide, in addition to
kerosene.  Science Wednesday  A Proton-M rocket, carrying a
Nimiq 6 communication satellite is raised to the launch pad at
the Russian-leased Kazakhstan's Baikonur cosmodrome, on May 14,
2012. Photo by STR/AFP/GettyImages.  After a Russian Proton-M
rocket lost control, tipped over and crashed in a fiery ball
over the Kazakh desert on Tuesday, plumes of black and orange
smoke could be seen hovering ominously over the crash site.  The
plume was partly due to rocket fuel that escaped during the
craft's plunge back to Earth. And this was not just any fuel,
but a highly corrosive, highly toxic propellant combination,
comprised of the chemical compounds hydr