I will assess here the Australian federal legislation covering CCS. If you are an overseas reader, I encourage you to read the legislation of your own country. My guess is that you will find similar defects there.
And the issue is not just that the defects are a problem in and of themselves. Probably more significant is this:
Looking at how the legislation is written, it is difficult to avoid the inference that the people who decided on the content of the legislation were fully aware that CCS is not a safe technology and that the companies that would deliver it are not confident that they can deliver safe and leak-proof CCS.
The federal government is obligated to assume liability after a so-called closure assurance period which may be as short as 15 years.
We may ask, rhetorically, why the companies doing carbon capture can't just get insurance for an indefinite period from a private sector insurer. The answer is, of course, obvious. No credible insurer will touch that kind of long-term risk. That does not mean the government should step in and effectively provide this insurance for free.
It could be deemed to be unreasonable to demand private sector insurance for an indefinite period knowing full well that this is not possible and would not be possible even if CCS were safe. Then why mention liability at all in the legislation? Here is what I believe the reason to be: Private sector companies will not get involved without their liability being legislated away because they are not confident that they can deliver safe and leak-proof CCS. And we are not talking about time frames like the lifetime of the planet. We are talking about the lifetime of the companies or possibly the lifetimes of the decision makers within those companies who might fear that they would be personally held accountable.
You would think that the legislation would be crystal-clear on the storage sites needing to be leak-proof. It is not.
The only place where leaks are mentioned explicitly is where the responsible federal minister has to deal with a "serious situation". The closest we come to storage sites needing to be leak proof in the certification requirements is that there is no "significant risk" of "significant adverse impact" on the environment.
Why not put something stronger? Something like this: "The responsible minister may only issue a licence to inject green house gases into a storage site if the applicant has demonstrated that the site, if established, used and sealed as planned, will be leak-proof for the life of the planet, barring a catastrophic and unlikely event such as a meteor impact". And then similar requirements when the site is closed and at the end of the closure assurance period. I am no mind reader but my educated guess is that the people who decided on the content of the legislation were aware that such a requirement can not be satisfied.