Fires in reactor #4 at the Fukushima nuclear power plant were most likely caused by hydrogen build-up or heat generated from spent fuel rods exposed to the atmosphere, or both. However, the later seems to be the case as fires were accompanied by very high levels of radiation issuing from the reactor -- the result of spent fuel rods breaking down and releasing poisonous radioactive particles into the environment due to loss of cooling.

The situation is clearly out of control though Japanese officials are attempting to 'play down' the emergency.

We look to the Corporatist directors of TEPCO, Tokyo Electric, to take the honourable course and commit hara-kiri for their gross negligence and failure to ensure safety by having adequate contingency plans in place in one of the world's most geologically unstable regions.

Japan Abandons Nuke Plant Over Radiation
http://www.youtube.com/watch?v=obHOBHDNlbs