Japan's Triple Disaster - Earthquake, Tsunami, and Nuclear Accident

 Two news items today (i) Japan's Nuclear Safety Agency will be transferred from the Ministry of Economy, Trade and Investment (METI) to the Ministry of Environment; and (ii) legislation has been drafted to make the government responsible for cleaning up the fallout from the troubled Fukushima nuclear plant, drew my attention to the massive task ahead in cleaning up the thousands of tonnes of solid waste, contaminated debris, and floating debris, still remaining from the triple disaster some 5 months ago.  A few days ago it was reported that there is a huge island of floating debris, including whole houses, cars, tractors and boats, stretching over about 70 kilometers, drifting towards the west coast of America, that will gradually hit the coast (and maybe a few ships) over the next 2-3 years.  

Once this debris material is in international waters, does it remain the responsibility of the Japanese Government to enforce its collection and removal?  On land, the responsibilities are clearer, although the ultimate share of the responsibility of TEPCO, the nuclear operator, is not completely clear.  The draft bill says that the Government will deal with radioactive contamination of the debris, wherever it is found, as well as soil contamination from atmospheric fallout, beyond allowable standards.  The bill also provides for the national and local governments to demand payment from TEPCO for the cost of the clean-up.  

A similar accident was narrowly averted in Dalian, China last week when a tropical storm overtopped a dyke protecting a chemical plant manufacturing paraxylene, a potentially toxic chemical used in fabric manufacture.  Local residents were evacuated as a precaution and subsequently protested, causing the local government to close the plant immediately and pledge to relocate it.

These, and other similar events, caused by the intersection of hazardous human activities and natural disasters, raises the question of the extent to which the private sector or the government should be held responsible.  Can the private sector justifiably claim that their chemical factory or nuclear plant was approved by the government to locate in a potentially hazardous zone, so it is not their responsibility if a natural disaster causes massive damage?  Or should the government claim that the private companies have a duty of care that includes taking adequate precautions against potential natural disasters, regardless of how remote the possibility might be?

I would be interested to hear the views of any members with a legal background (which I don't have, by the way) on where the correct balance lies in assigning responsibilities for pollution incidents occasioned by natural disasters.  And while you are at it can someone enlighten me on the extent of Japan's responsibility to clean up the floating debris, once in international waters?