What seems to be the problem?
The liability issue concerns financial responsibility for stored CO2 in the short and long term. IPCC estimates that more than 99% of the stored CO2 is "very likely" to remain in storage after 100 years and that over 99% of the stored CO2 is "likely" to remain in storage after 1000 years. In spite of this assessment leakages and accidents can happen and these are to be covered financially by the store manager. The history of technology abounds with events that could not happen did happen anyway. The timescale of climate problems and the durability of storage goes far beyond a traditional business perspective which raises the question of long-term liability for storage maintenance, monitoring and coverage when leakages occur. The future store operators will be financially motivated to pass on liabilities to public authorities as soon as possible or as soon as stores are full. If this happens, there is a risk that future generations of taxpayers will have to pay all costs that may arise in relation to stores.
Although the security issue and the time horizon is not readily comparable to that of disposal of radioactive waste from nuclear power plants both of these large scale technologies assume that societies will remain stable for hundreds of years at a high technical and financial level to ensure that monitoring and actions in case of leakages or accidents can take place.
How does the EU tackle the issue of storage liability ?
See this link: Storage Liability in the EU