September 2021, Vol. 248, No. 9


Performance Measures Needed to Assess Liquid Pipeline Regulations

By U.S. Government Accountability Office (GAO)  

The U.S. liquid pipeline network runs for more than 220,000 miles (354,000 km) and is critical to the economy. Pipelines are considered a relatively safe way to transport crude oil and other hazardous liquids, but accidents can happen.  

The Pipeline and Hazardous Materials Safety Administration (PHMSA) amended safety regulations in 2019. Stakeholders said the changes could improve safety without presenting significant challenges. However, several operators said they would need to modify or replace pipelines to accommodate certain inspection tools.   

PHMSA has not developed measures to assess whether the changes improve safety. We recommended doing so.  

What GAO Found  

In 2019, PHMSA issued a final rule amending its hazardous liquid pipeline safety regulations. Selected pipeline operators and officials from PHMSA and selected states’ pipeline safety offices said that these changes would enhance pipeline safety and present no significant challenges.   

They said the most beneficial changes expanded the scope of inspections. For example, in addition to existing requirements for operators to use specialized tools to inspect pipelines in “high-consequence areas” – defined by population and environmental factors – the 2019 Rule requires such inspections outside of those areas.   

While operators noted the rule’s potential to improve safety, all 11 operators GAO interviewed identified specific amendments that could increase their costs. For example, several operators said they would need to modify or replace some of their pipeline to allow for certain inspection tools required by the changes.  

PHMSA and state pipeline safety officials said they did not anticipate oversight challenges or additional costs because the changes did not alter their inspection process.  

Specialized In-Line Inspection Tool Being Placed in a Launch Point on a Pipeline  

PHMSA held meetings with and provided guidance to operators and inspectors on the changes but has not developed measures to assess if the changes improve safety. Leading performance management practices call for agencies to track progress toward goals using measures that include targets for expected levels of performance and time frames.   

While PHMSA has desired outcomes for the 2019 Rule, including safety improvements, PHMSA officials said they have not established performance measures for those outcomes because some of the changes have long-term compliance deadlines, and so data are not yet available to assess effectiveness.  

However, other changes have shorter-term deadlines for compliance, and PHMSA could use data it already collects from operators for its assessment. Without performance measures, PHMSA cannot determine whether the changes made by the 2019 Rule are achieving their intended outcomes and contributing to PHMSA’s safety goals.  

In 2016, a pipeline safety statute included a provision for GAO to report on hazardous liquid pipeline safety after PHMSA issued a specific final rule amending its safety regulations, which it did in 2019. This report examines (1) perspectives of selected pipeline stakeholders on the benefits and challenges of the amendments made by the 2019 Rule and (2) steps PHMSA has taken to inform stakeholders of these amendments and to measure their effects on pipeline safety.   

GAO reviewed relevant statutes and regulations; analyzed PHMSA accident data from calendar years 2011–2020; interviewed 11 pipeline operators – selected by pipeline type, miles and product type – as well as pipeline industry and safety stakeholders, and PHMSA and pipeline safety officials from six states.  


PHMSA should develop and use performance measures to assess whether the changes made as required by the 2019 Rule achieve desired outcomes and improve safety. The Department of Transportation concurred with GAO’s recommendation.   

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