PHMSA Issues Proposed Rule Seeking to Impose Enhanced Safety and Operational Requirements on Carbon Dioxide Pipelines
On January 10, 2025, the Pipeline and Hazardous Materials Safety Administration ("PHMSA") issued a proposed rule setting forth revisions to the federal Pipeline Safety Regulations ("PSR") (49 C.F.R. Parts 190-99) to include safety standards and reporting requirements for all phases of carbon dioxide pipelines. PHMSA states that the revisions are in response to multiple events, including congressional mandates directing PHMSA to regulate both carbon dioxide in gas as well as (sub-critical) liquid phases, anticipated expansions of pipeline infrastructure transporting carbon dioxide in all phases based on initiatives to address climate change (e.g., in conjunction with carbon capture, sequestration, and storage activities), and lessons learned from the February 22, 2020, rupture of a supercritical-phase carbon dioxide pipeline near Satartia, Mississippi.
The rule describes 18 proposed changes to the PSR. PHMSA first proposes to expand the scope of the regulations "to ensure more carbon dioxide pipelines are subject to meaningful safety and reporting requirements" set forth in Part 195 of the PSR. The revisions would accomplish this by first extending the PSR to regulate not only supercritical-phase carbon dioxide, but carbon dioxide in the gas and liquid phases as well. PHMSA also proposes to lower the threshold of carbon dioxide molecules needed to be present in the product stream in order to qualify as a "carbon dioxide" pipeline. The new threshold would include pipelines that have greater than 50% of carbon dioxide molecules in their product stream, as compared to the current threshold of more than 90%.
The rule also contains revisions that seek to enhance the design and operation requirements for carbon dioxide pipelines. These enhancements cover:
- The design of carbon dioxide pipelines, with a specific focus on mitigating fracture propagation through the pipe;
- The "conversion to service" requirements for pipelines converted from non-regulated to Part 195-regulated service, whether transporting hazardous liquid or carbon dioxide;
- The requirement of highly volatile liquid ("HVL") pipelines, including carbon dioxide pipelines, to perform vapor dispersion analyses in connection with determinations of whether a release from a pipeline could affect a high-consequence area, such as a commercially navigable waterway, populated area, or drinking water or ecological resource area unusually sensitive to environmental damage from a pipeline release;
- Right-of-way inspection requirements for pipelines transporting hazardous liquids and carbon dioxide; and
- The depth of cover classifications for agricultural areas.
Additional revisions propose that pipeline operators adopt new or supplementary safety mechanisms, starting with safety at the pipeline itself. PHMSA advises that operators be required to implement: (i) a leak detection system for each carbon dioxide pipeline, with additional monitoring requirements for pipelines transporting supercritical- or liquid-phase carbon dioxide; (ii) a fixed vapor detection and alarm system at specific facilities on pipelines transporting HVLs, including carbon dioxide; and (iii) a monitoring and mitigation program for corrosion-affecting constituents within carbon dioxide product streams.
Other amendments and additions to the regulations seek to extend operators' safety requirements from the pipeline into the surrounding communities. PHMSA proposes that carbon dioxide pipeline operators proactively engage with local communities by providing training and appropriate equipment to local emergency responders in the event of a carbon dioxide release. If an emergency response becomes necessary, the proposed regulations also impose robust requirements on pipeline operators to communicate with the public during the emergency event.
Consistent with President Trump's executive order titled "Regulatory Freeze Pending Review," the proposed rule has not been published in the Federal Register so that it can be reviewed by the new administration. It is unclear what action the new administration will take upon its review.
