So why ignore that fact? From The Hindu:
The ongoing disaster of the petroleum volcano caused by blowout of the BP oil well in the Gulf of Mexico should provide a sobering object lesson. Thinking that does not consider high-consequence but low-probability events borders on folly. BP also considered an uncontrolled blowout to be very low probability. As it turns out, BP, as one of the world's largest corporations, can provide the tens of billions of dollars of damages. But no nuclear company in the United States has the financial muscle to compensate a significant fraction of the maximum officially estimated damages.Makes sense.