Often, states choose to cap the liabilities of companies operating dangerous facilities like oil rigs or nuclear power stations. They recognize that companies are hesitant to build or own such things, as long as they might be called upon to pay the full cost associated with any accidents.
Of course, providing these caps is a deeply anti-market thing to do. There are very good reasons to worry about oil spills and nuclear disasters, and heavy costs are borne by many people when they occur. Those risks should be foremost in the minds of people who choose to invest in these facilities.
When governments grant companies ‘protection’ against massive claims in the event of disasters, they are saying that building these facilities is so important that it should be done even if there may ultimately be serious uncompensated harm imposed on the general public. This takes the illusory profits associated with environmentally harmful economic activities to a new level, by saying that even in cases where companies can be proven to have directly caused harm to third parties, in the pursuit of their own profits, those profits will be protected by the wealth and authority of the states.