Oil and gas fields and salt domes have been used successfully for several decades to store a variety of substances and products, including natural gas and other hydrocarbon products. Over the years, strong international standards and monitors have minimized leaks and other potential problems.
The geological formations that make up oil and gas fields are solid rock. Oil, gas, water and, sometimes, naturally occurring carbon dioxide have resided securely in the interstices between rock grains for millions of years. This gives confidence that CO2 can now be similarly stored securely in the same underground environments.