Sept. 10, 2018

U.S. Department of Transportation Should Revisit Federal Safety Regulations for Liquid Petroleum Gas Distribution Systems, Says New Report

WASHINGTON -- Current federal safety regulations for small distribution systems used for propane and other liquefied petroleum gases (LPGs) should be improved for clarity, efficiency, enforceability, and applicability to risk, says a new report from the National Academies of Sciences, Engineering, and Medicine. Because compliance with the federal regulations is not enforced consistently by states, there is little understanding of how the requirements affect the safety of the gas pipeline systems, particularly the smallest ones with fewer than 100 customers.

While most LPG systems consist of a storage tank and supply lines that serve a single home or business, some systems are configured to deliver LPG to multiple homes or businesses. When these multi-user systems serve 10 or more customers, or if they have two or more customers and part of the system is located in a public place, they become subject to federal safety regulations administered by the Pipeline and Hazardous Materials Safety Administration (PHMSA) of the U.S. Department of Transportation. The federal regulations, which are LPG-specific and apply to all LPG systems regardless of the number of customers, supplement the safety standards of the National Fire Protection Association (NFPA). In most cases, states enforce the federal regulations as well their own regulations and the NFPA codes.

Congress asked for a study of whether the federal regulatory requirements, which also apply to large natural gas distribution systems, are appropriate for small LPG systems that must already comply with the NFPA codes. The committee that carried out the study and wrote the report reviewed records of pipeline incidents and found that serious incidents involving LPG distribution system are infrequent. The committee also found evidence that many small multi-user LPG systems are not being inspected regularly for compliance with federal regulations, possibly due to inconsistent regulatory interpretations about when a system falls under the requirements and state regulators having limited resources to identify and inspect the smaller systems. An apparent source of state-to-state variability in enforcement is different interpretations by states and operators about what constitutes a “public place.”

Without more complete information on the number, location, configuration, and condition of multi-user LPG systems, the committee said it would be a mistake to make changes to the safety regulatory framework based on simple criteria such as the number of customers on a system. Therefore, the committee recommended that a series of steps be taken to better identify the location, condition, and risk characteristics of small multi-user systems and to ensure that the regulatory requirements and their enforcement are appropriate to those risks.

Congress should direct PHMSA to ensure the term “public place” is uniformly interpreted by regulators and LPG pipeline operators alike, the committee said. Operators of LPG pipeline systems also should be required to report to regulators the location, number, and safety performance of their systems that fall under federal jurisdiction. Once those systems have been identified and inspection activity confirmed by states, PHMSA should allow individual states to develop a waiver program that allows operators to opt out of federal requirements that the state has determined are not in line with the risk presented by the operator’s system. The report notes each state should be required to obtain PHMSA’s approval of its waiver program and have it periodically renewed by the safety agency.

The study was sponsored by the U.S. Department of Transportation. The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. The National Academies operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln. For more information, visit A committee roster follows.

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Copies of Safety Regulation for Small LPG Distribution Systems are available at or by calling 202-334-3313  or 1-800-624-6242. Reporters may obtain a copy from the Office of News and Public Information (contact listed above).

Transportation Research Board

Committee for a Study on Propane Gas Pipeline Facilities

Craig E. Philip
Research Professor of Civil and Environmental Engineering, and
Director, Vanderbilt Center for Transportation Research
Vanderbilt University
Nashville, Tenn.

Samuel T. Ariaratnam
Professor and Construction Engineering Program Chair
Ira A. Fulton Schools of Engineering
Arizona State University

Bruce Benson
Public Utilities Engineer
Public Utilities Regulatory Authority
State of Connecticut Department of Energy and Environmental Protection
New Britain

Robert J. Chipkevich
Chipkevich Safety Consulting Group
Brentwood, Tenn.

Sara Rollet Gosman
Assistant Professor
School of Law
University of Arkansas

Stephanie A. King
Senior Director
Model Development
Risk Management Solutions Inc.
Newark, Calif.

Philip J. Oakes
Director of National Programs
National Association of State Fire Marshals
Cheyenne, Wyo.

April Richardson
Alternative Fuels Safety Department
Railroad Commission of Texas

Ross T. Warnell
Owner and Principal
The Propane Doctor
Kansas City, Kan.


Micah Himmel
Staff Officer