Question: What are the environmental concerns around CO2 pipelines?

This one is difficult. Carbon dioxide isn't transported through pipelines as a gas. Instead, they are talking about sending it through as a supercritical fluid. It means the lines need to be higher pressure than normal ( i.e. new) and may lead to new dangers. And yes, line breaks will be an issue.

A staff member from the Pipeline Safety Trust (referenced in the Grist article linked by @Pat above) had some great insights to share on this issue:

1. For more info on risks with CO2 pipelines that current regulations aren’t equipped to assess, they have a brief background document on CO2 pipelines here (in addition to the full report here)

2. On ways that concerned residents near proposed CO2 pipeline projects might learn more and advocate for improved regulations, they suggested (in addition to reading the report):

   • “...look at the companies proposing these pipelines (Navigator, Summit, etc.) and find when and where their public meetings are happening and then make sure to attend and voice concern...all the companies proposing lines in the Midwest are currently making the rounds in the public and local meeting circuit. These companies are all still in the stage of gathering easements. Eminent domain is a huge issue surrounding these proposed pipelines and tons in the Midwest states are trying to fight it.”
   • “...there are some other organizations also working hard on the issue of CO2 pipelines, such as the Iowa chapter of the Food & Water Watch and Bold Alliance (based in Nebraska)…reach out to these organizations to find out more information on how they can assist.”
   • “It’s probably also helpful…to contact their local governments to let them know about the gravity of this issue and see if their local governments can be of any assistance moving forward.”