Many of the liability related risks can be predicted from experience with industrial chemistry and oil production. Commercial liability risks would depend on the economic model imposed by policy makers. Long term liability for stored CO2 [to be stored for hundreds of years] would probably damage the economic case for private industry investment and operation of CCS. The current practice of dumping CO2 into the atmosphere incurs no third party commercial liabilities and is usually free of liabilities for personal injury or environmental harm.
House of Commons Science and Technology Committee. February 2006.
“Meeting UK Energy and Climate Needs: The Role of Carbon Capture and Storage”
The risk is that storage would be insecure. Gradual release of CO2 over a period of decades or less would defeat the object, sudden release could, in addition, cause localised temporary toxicity and possibly loss of life and property through physical effects and asphyxiation. Testing the long term security of storage should a high priority if this technique is to be applied on the required scale.