Pipeline Safety Basics
Fossil fuel pipelines are categorized and regulated by what they transport and where they go. Understanding these categories and regulations is important because they determine how pipelines are both constructed and safety is monitored and possibly regulated. These pipelines transport a variety of fuels including gasoline, natural gas, propane, hazardous liquids, diesel, and jet fuel.
Safety discussions about fossil fuel pipelines generally make a distinction between two types of products in the pipeline:
- Hazardous Liquid Pipelines that carry fuels such as gasoline, diesel, jet fuel, and other flammable and hazardous liquids.
- Gas Pipelines that carry natural gas and propane.
Once placed into the ground and/or in-service, the safe transportation of these two types of products are federally regulated by two sets of U.S. Department of Transportation Regulations, 49 Code of Federal Regulations (CFR) Parts 190, 191, 192, and 196 for gas pipelines, and 49 CFR Parts 190, 194, 195, and 196 for hazardous liquid pipelines. Separate U.S. Department of Transportation regulations for liquified natural gas (LNG) are found under 49 CFR Part 193.
The rapid and widespread development of onshore unconventional oil and gas fields across the United States and Canada has added new dimensions to these safety discussions and the regulatory environment. The distinction between conventional and unconventional fossil fuels is important in terms of the expansion and adoption of new pipeline terms, definitions of use, emerging risks, and applicable regulations. The fossil fuel pipeline industry’s proposals for increasing the capacity of current infrastructure with new pipeline miles and new compressor stations and LNG facilities raises important and new questions about safety related to pipeline classifications in agricultural, suburban, and urban communities.
Pipeline Systems: The Wellhead to Consumer Infrastructure

Pipeline infrastructure is a system and it is helpful in communicating about the safety and risks to know what each part of the system is called and to understand how the different pieces of the system fit together. A discussion of pipeline infrastructure is incomplete without starting at the source, the wellhead and the production formation, or underground fossil fuel reservoir, and ending with the delivery of that fossil fuel to the residential, industrial, or commercial consumer. In a typical pipeline infrastructure system there are four parts:
- Production: Piped wellhead locations that take raw natural gas or liquids from underground formations.
- Gathering and Processing: Pipeline facilities that strip out impurities and other hydrocarbons and fluids to produce pipeline grade gas and other gas and liquid by-products for transmission or disposal.
- Transmission: Pipeline facilities that deliver gas and liquids from the wellhead and processing plant to city gate stations or industrial end users. Transmission occurs through a vast network of high pressure pipelines, including facilities such as compressor stations and valve stations. Natural gas and hazardous liquids storage falls within this sector. Storage can be in above ground tanks or in depleted underground reservoirs, aquifers, and salt caverns.
- Distribution: Pipeline facilities that deliver gas and liquids from the transmission pipeline via the city gate to the end user and consumer (e.g., residential, commercial and industrial).
Safe Pipelines Begin at Route Selection, Design, and Construction
In the case of new, or enhancements to existing, interstate transmission pipelines (but not gathering pipelines) PHMSA, FERC, and/or some States safety oversight responsibilities may begin during siting and construction. {ADD LINK TO REGULATIONS PAGE}.
According to PHMSA, there are 12 distinct steps to constructing a new pipeline:
- Route Selection
- Regulatory Processes
- Design
- Site Preparation
- Pipe Stringing
- Trenching
- Bending
- Welding
- Coating
- Lowering and Backfilling
- Testing
- Site Restoration
Federal and State Pipeline Safety Inspections and Investigations
PHMSA’s Office of Pipeline Safety (OPS) Field Operations, as of November 2018, employed 213 staff to conduct compliance inspections, incident and accident investigations, and enforcement actions on interstate pipeline systems and on intrastate pipeline systems in states that do not have their own programs. In addition, PHMSA inspectors have the responsibility of overseeing stakeholder outreach, education, and training activities, including excavator damage prevention communications.
Funded largely by PHMSA, States with their own pipeline safety programs (see HERE) employ a total of 382 pipeline safety inspectors nationwide as of November 2018.
These 582 federal and state pipeline safety inspectors are responsible for conducting inspections on almost 3,000 companies that operate 2.8 million miles of pipelines, 152 liquefied natural gas plants, 403 underground gas storage fields, and 8,124 hazardous liquid breakout tanks. Here is a breakdown of how federal inspectors allocated their time in 2017-2018:
- 8% inspecting the construction of new pipeline facilities.
- 4% investigating pipeline system failures.
- 52% inspecting pipeline facilities for compliance with PHMSA operation, maintenance, integrity, and emergency response safety regulations.
- 14% communicating with stakeholders, especially on excavation damage prevention and land use planning.
- 6% working on internal teams to continuously improve inspection methodologies and business processes.
- 17% training.
Operator Compliance Programs
PHMSA encourages operators subject to the agency’s safety regulations and oversight to develop rigorous compliance programs that help minimize the potential for violations.
In December 2016, the Secretary of Transportation convened the Voluntary Information-sharing System Working Group (VIS WG) to consider the development of a voluntary information-sharing system to encourage collaborative efforts among operators and other safety stakeholders to improve inspection information feedback and information sharing with the purpose of improving gas transmission and hazardous liquid pipeline facility integrity risk analysis (mandated by section 10 of the Protecting our Infrastructure of Pipelines and Enhancing Safety (PIPES) Act of 2016 (Public Law 114-183)). The VIS WG Recommendation Report was transmitted to the Secretary in April 2019. The Working Group recommended including gas distribution systems in the effort, and laid out a series of recommendations designed to fulfill two related, and currently unmet, safety needs:
1. The need for the pipeline industry to implement an overarching and rigorous pipeline safety management system (SMS) process to evaluate, prioritize, and create comprehensive risk reduction programs that lead to a continuous improvement model for pipeline safety (See API RP 1173.)
2. The need to continuously improve system knowledge and pipeline-specific data to analyze and mitigate pipeline safety risks through a comprehensive, systematic, and integrated way to gather, evaluate, quantify, and share critical pipeline safety data and recommended remediation measures or lessons learned of all types to operators across the various industry segments (hazardous liquid transmission, gas transmission, gas distribution) in an efficient and confidential manner.
Federal Enforcement of Pipeline Safety
PHMSA’s Pipeline Safety Enforcement Program has responsibility (under 49 CFR 190, Subpart B) for ensuring hazardous liquids and gas pipelines meet federal regulatory requirements for safe, reliable, and environmentally sound operations. An overview of the Enforcement Program is found here. PHMSA also has authority to prevent and enforce penalties on damages to pipeline infrastructure from third-party excavation.
Here is a list of PHMSA enforcement activity from 2002 to the present. The status of enforcement cases and other statistics about PHMSA’s enforcement activity can be found here.