On a February evening in 2020, a carbon dioxide (CO₂) pipeline ruptured near Satartia, Mississippi, causing a plume of CO₂ to engulf the community. Within minutes, dozens of residents collapsed in their homes and vehicles. Cars stalled, including emergency vehicles trying to reach the scene. The incident hospitalized 45 Satartia residents and forced 200 to evacuate from their homes.

There are currently 5,000 miles of CO₂ pipelines in the United States, most of which, like the pipeline that ruptured near Satartia, transport CO₂ to oil fields to pump more oil out of aging wells through a process called enhanced oil recovery. Unprecedented federal investment in carbon capture and sequestration (CCS) — an expensive technology that is unproven to effectively curb climate change-causing pollution — will require a massive expansion of this CO₂ pipeline network.

CO₂ pipelines pose unique risks from other types of pipelines and are currently under-regulated by the Pipeline and Hazardous Materials Safety Administration (PHMSA). Local, state, and federal authorities must take action to ensure the safer construction and operation of these pipelines.

What should we know about CO₂ pipelines in the Ohio River Valley?

The Inflation Reduction Act and other federal legislation and rules have authorized billions of dollars to be allocated to CCS projects around the U.S. In order for CCS to work as intended, infrastructure would need to be constructed to transport CO₂ from emissions sources (such as hydrogen and ammonia facilities) to wherever it will be stored (such as injection wells). Tens of thousands of miles of CO₂ pipelines would need to be constructed throughout the U.S. to accomplish this.

The Department of Energy recently approved $30 million in funding for the Appalachian Regional Clean Hydrogen Hub (ARCH2), with components in Ohio, Pennsylvania, and West Virginia. ARCH2 would use fracked methane gas to produce hydrogen, with CCS supposedly being used to capture the CO₂ byproduct of this process. Hydrogen produced using methane from fossil gas (aka “natural gas”) and CCS is called “blue hydrogen.” According to the ARCH2 developers, CO₂ captured from the blue hydrogen production would be “transferred via pipeline to geologic sequestration.” To date, ARCH2 has not been forthcoming about where exactly it plans to transport and store captured CO₂, but many miles of CO₂ pipeline construction would need to be part of the project.

CCS projects already have poor or unproven safety and effectiveness records. CO₂ pipelines are a big piece of this dirty, expensive puzzle.

Why are CO₂ pipelines dangerous?

The transport of CO₂ poses unique risks to the integrity of pipelines. The transport of CO₂ can cause “ductile fractures,” where a CO₂ pipeline will “unzip,” exposing extended distances of ruptured pipeline.

CO₂ in pipelines can become dangerous when it mixes with water and other common impurities. For example, water mixing into a CO₂ stream can form carbonic acid, which is corrosive to the carbon steel that most pipelines are made of. Another common contaminant in pipeline CO₂ is hydrogen sulfide, which is flammable and toxic.

CO₂ is an intoxicant and it displaces oxygen in the air, which can cause disorientation, confusion, unconsciousness, and even suffocation to people and animals exposed to a pipeline rupture. This can also prevent emergency vehicles with combustion engines from reaching the scene of a rupture, and likewise, can make it challenging to escape a plume.

Each of these risks came to fruition in Satartia. The pipeline underwent a ductile fracture. In addition to the CO₂ plume, Satartia residents were exposed to a noxious green cloud of hydrogen sulfide. Dozens of people were hospitalized due to the plume, suffering the effects of CO₂ poisoning or exposure.

How can CO₂ pipelines become safer?

Right now, CO₂ pipelines are largely unregulated. After the Satartia incident, Congress mandated that PHMSA promulgate safety rules for CO₂ pipelines. In the meantime, the dangers of the operational CO₂ pipelines persist: in April, 2,548 barrels of CO₂ leaked from a pipeline in Sulphur, Louisiana. A leak has also recently been reported in Illinois at the first operational CO₂ injection well in the U.S., shedding light on the challenges of CCS.

There is a lot of uncertainty about how CO₂ pipelines can be constructed and operated safely, including the appropriate pipeline construction to avoid leaks and ruptures. The current regulations of CO₂ pipelines are suited for enhanced oil recovery, rather than the transport of carbon for permanent sequestration. Further, industry players have proposed converting the Ohio River Valley’s large network oil and gas pipelines into CO₂ pipelines, despite the unique requirements for these types of pipelines to operate safely.

We must urge PHMSA to promulgate safety rules for CO₂ pipelines that maximize community protections, including by regulating CO₂ in all of its phases and ensuring that pipeline operators identify appropriate potential impact areas in the event of ruptures. Much more research must be done about the efficacy of CO₂ pipeline construction techniques, and particularly whether oil and gas pipelines can safely be converted to CO₂ pipelines, before any large-scale buildout. We must continue to highlight the potential impacts of CO₂ pipelines whenever CCS projects are proposed in the Ohio River Valley.