PIPELINE SAFETY

Collecting Data and 

Sharing Information 

on Federally 

Unregulated Gathering 

Pipelines Could Help 

Enhance Safety

Report to Congressional Requesters

March 2012

GAO-12-388

United States Government Accountability Office

GAO
United States Government Accountability Office

Highlights of GAO-12-388, a report to 

congressional requesters 

March 2012 

PIPELINE SAFETY

Collecting Data and Sharing Information on 

Federally Unregulated Gathering Pipelines Could 

Help Enhance Safety

Why GAO Did This Study

Pipelines are a relatively safe mode of 

transportation for hazardous liquid and 

natural gas and are regulated by the 

Department of Transportation’s (DOT) 

Pipeline and Hazardous Materials 

Safety Administration (PHMSA) and 

state entities. Included in the nation’s 

pipeline network are an estimated 

200,000 or more miles of onshore 

“gathering” pipelines, which transport 

products to processing facilities and 

larger pipelines. (See figure.) Many of 

these pipelines have not been subject 

to federal regulation based on their 

generally rural location and low 

operating pressures. While incidents 

involving gathering pipelines regulated 

by PHMSA have resulted in millions of 

dollars in property damage in recent 

years, comparable statistics for 

federally unregulated gathering 

pipelines are unknown. This report 

identifies (1) the safety risks that exist, 

if any, with onshore hazardous liquid 

and natural gas gathering pipelines 

that are not currently under PHMSA 

regulation and (2) the practices states 

use to help ensure the safety of these

pipelines. GAO surveyed state pipeline 

safety agencies in all 50 states and the 

District of Columbia; interviewed 

officials at PHMSA, state pipeline 

safety agencies, pipeline companies, 

and industry associations; and 

analyzed data and regulations. 

What GAO Recommends

DOT should (1) collect data on 

federally unregulated hazardous liquid 

and gas gathering pipelines and 

(2) establish an online clearinghouse 

or other resource for sharing

information on pipeline safety 

practices. DOT provided technical 

corrections on a draft of this report.

What GAO Found

While the safety risks of onshore gathering pipelines that are not regulated by 

PHMSA are generally considered to be lower than for other types of pipelines, 

PHMSA does not collect comprehensive data to identify the safety risks of

unregulated gathering pipelines. In response to a GAO survey, state pipeline 

safety agencies cited construction quality, maintenance practices, unknown or 

uncertain locations, and limited or no information on pipeline integrity as among 

the highest risks for federally unregulated pipelines. Without data on these risk 

factors, pipeline safety officials are unable to assess and manage safety risks 

associated with these pipelines. Furthermore, changes in pipeline operational 

environments cited in response to GAO’s survey and by industry officials could 

also increase safety risks for federally unregulated gathering pipelines. 

Specifically, land-use changes are resulting in development encroaching on 

existing pipelines and the increased extraction of oil and natural gas from shale 

deposits is resulting in the development of new gathering pipelines, some of 

which are larger in diameter and operate at higher pressure than older pipelines. 

PHMSA is considering collecting data on federally unregulated gathering 

pipelines, but the agency’s plans are preliminary, and the extent to which 

PHMSA will collect data sufficient to evaluate the potential safety risks 

associated with these pipelines is uncertain. 

A small number of state pipeline safety agencies GAO surveyed reported using at 

least one of five practices that were most frequently cited to help ensure the safety 

of federally unregulated pipelines. These practices include (1) damage prevention 

programs, (2) considering areas of highest risk to target resources, (3) safety 

inspections, (4) public outreach and communication, and (5) increased regulatory 

attention on operators with prior spills or leaks. However, the sharing of information 

among states on the safety practices used appears to be limited. Some state and 

PHMSA officials GAO interviewed had limited awareness of safety practices used 

by other states. Increased communication and information sharing about pipeline 

safety practices could boost the use of such practices for unregulated pipelines.

However, information targeted at gathering pipelines on PHMSA’s website, 

including relevant safety practices and state activities, is limited.

Pipeline System

View GAO-12-388. For more information, 

contact Susan A. Fleming at (202) 512-2834 

or flemings@gao.gov. 
Page i GAO-12-388 Pipeline Safety 

Letter 1 

Background 2

Limited Information on Safety Risks and Changing Operational 

Environments Are Leading PHMSA to Consider Collecting Data 9

States Could Benefit from Sharing Safety Practices 19

Conclusions 28

Recommendations for Executive Action 29

Agency Comments 30

Appendix I Objectives, Scope, and Methodology 31

Appendix II Summary Results, GAO Pipeline Safety Regulations Survey 34

Appendix III GAO Contact and Staff Acknowledgments 36

Table

Table 1: PHMSA Class Designations for Gas Pipelines 6

Figures

Figure 1: Pipeline System 4

Figure 2: Interstate and Intrastate Agents for PHMSA 8

Figure 3: Excavation Damage 11

Figure 4: Changing Land Use around Pipelines 12

Figure 5: Current and Prospective Shale Gas Regions 14

Figure 6: Number of Incidents for All Federally Regulated Pipeline 

Systems, 2004 through 2010 17

Figure 7: Total Property Damage for All Regulated Pipeline 

Systems, 2004 through 2010 17

Figure 8: Most Frequently Used Safety Practices by States for 

Gathering Pipelines 20

Figure 9: Pipeline Marker 22

Figure 10: Examples of Rural and Residential Gathering Pipeline 

Operational Environments near Dallas-Fort Worth 24

Figure 11: Gathering Pipeline Construction Documentation in 

Texas 25

Contents
Page ii GAO-12-388 Pipeline Safety 

Abbreviations

ANPRM Advanced Notice of Proposed Rulemaking

DOT Department of Transportation

NAPSR National Association of Pipeline Safety Representatives

PHMSA Pipeline and Hazardous Materials Safety Administration

psi pounds per square inch

This is a work of the U.S. government and is not subject to copyright protection in the 

United States. The published product may be reproduced and distributed in its entirety 

without further permission from GAO. However, because this work may contain 

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Page 1 GAO-12-388 Pipeline Safety 

United States Government Accountability Office 

Washington, DC 20548

March 22, 2012

The Honorable John D. Rockefeller IV

Chairman

Committee on Commerce, Science, 

and Transportation

United States Senate

The Honorable Frank R. Lautenberg

Chairman

Subcommittee on Surface Transportation 

and Merchant Marine Infrastructure, 

Safety, and Security

Committee on Commerce, Science, and Transportation

United States Senate

Pipelines are a relatively safe mode of transportation for hazardous liquid 

and natural gas. The nation’s network of more than 2.5 million miles of 

pipeline is largely regulated by the Department of Transportation’s (DOT) 

Pipeline and Hazardous Materials Safety Administration (PHMSA) and 

state entities. Part of this network consists of more than 200,000 miles 

(estimated) of onshore “gathering” pipelines, which transport hazardous 

liquid and natural gas products from wells to processing facilities and to 

larger transmission pipelines. Many of these gathering pipelines, 

however, have not been subject to PHMSA regulation because they are 

generally located away from population centers and operate at low 

pressures.1

You requested that we review pipeline safety issues related to onshore 

gathering pipelines not regulated by PHMSA. To do so, we examined 

(1) the safety risks that exist, if any, with onshore hazardous liquid and 

natural gas gathering pipelines that are not currently under PHMSA 

In recent years, incidents involving gathering pipelines 

regulated by PHMSA have resulted in millions of dollars in property 

damage. Comparable statistics for federally unregulated gathering 

pipelines are unknown because PHMSA does not collect such data.

 

1PHMSA has limited statutory authority to regulate such pipelines under 49 U.S.C. 

§ 60101(b). 

 
 

Page 2 GAO-12-388 Pipeline Safety 

regulation and (2) the practices states use to help ensure the safety of 

these federally unregulated onshore gathering pipelines.

To identify safety risks that may be associated with gathering pipelines, 

we reviewed PHMSA safety regulations and analyzed data on pipelines 

regulated by PHMSA to understand the types of pipeline data currently 

collected, as well as to compare and analyze accident, injury, fatality, and 

other trends. We determined that these data were complete, reasonable, 

and sufficiently reliable for the purposes of this report. For both 

objectives, we developed and administered a survey to 52 pipeline safety 

agencies2

We conducted this performance audit from February 2011 to March 2012 

in accordance with generally accepted government auditing standards. 

Those standards require that we plan and perform the audit to obtain 

sufficient, appropriate evidence to provide a reasonable basis for our 

findings and conclusions based on our audit objectives. We believe that 

the evidence obtained provides a reasonable basis for our findings and 

conclusions based on our audit objectives.

in all 50 states and the District of Columbia to collect 

information on, among other things, onshore gathering pipelines, the 

perceived pipeline safety risks associated with those pipelines, and the 

safety practices used for those pipelines. We received a 100 percent 

response rate for this survey. We also interviewed officials at PHMSA, 

selected state pipeline safety agencies, pipeline companies, and industry 

associations. We conducted site visits to Dallas-Fort Worth, Denver, and 

Pittsburgh; we selected these locations based on geography, existing 

pipeline infrastructure, and other factors.

Pipelines transport roughly two-thirds of domestic energy supplies 

through approximately 2.5 million miles of pipelines throughout the United 

States. These pipelines carry hazardous liquids and natural gas from 

producing wells to end users (residences and businesses). Within this 

nationwide system, there are three main types of pipelines.

 

2

Two state pipeline safety officials from separate agencies in Arkansas that are 

responsible for overseeing pipeline safety in that state responded to our survey. Also, 

Alaska and Hawaii have chosen not to participate in pipeline arrangements with PHMSA. 

Therefore, a PHMSA official who conducts state pipeline safety inspections in these states 

responded to those states’ surveys. 

Background
 

Page 3 GAO-12-388 Pipeline Safety 

• Gathering pipelines. Gas gathering pipelines collect natural gas from 

production areas, while hazardous liquid gathering pipelines collect oil 

and other petroleum products. These pipelines then typically transport

the products to processing facilities, which in turn refine and send the 

products to transmission pipelines. According to PHMSA officials, 

traditionally, gathering pipelines range in diameter from about 2 to 12 

inches and operate at pressures that range from about 5 to 800 

pounds per square inch (psi). These pipelines tend to be located in 

rural areas but can also be located in urban areas. PHMSA estimates 

there are 200,000 miles of gas gathering pipelines and 30,000 to 

40,000 miles of hazardous liquid gathering pipelines.

• Transmission pipelines. Transmission pipelines carry hazardous liquid 

or natural gas, sometimes over hundreds of miles, to communities 

and large-volume users (e.g., factories).3 For natural gas transmission 

pipelines, compression stations located periodically along the pipeline 

maintain product pressure. Similarly, pumping stations along 

hazardous liquid transmission pipelines maintain product flow. 

Transmission pipelines tend to have the largest diameters and 

pressures of any type of pipeline, generally ranging from 12 inches to 

42 inches in diameter and operating at pressures ranging from 400 to 

1440 psi.4

• Distribution pipelines. Gas distribution pipelines continue to transport 

natural gas to residential, commercial, and industrial customers, 

splitting off from transmission pipelines. These pipelines tend to be 

smaller, sometimes less than 1 inch in diameter, and operate at lower 

pressures—0.25 to 100 psi.

PHMSA has estimated there are more than 400,000 miles 

of gas and hazardous liquid transmission pipelines.

5

 

3

For the purposes of this report, we use the term transmission pipeline to refer to both 

hazardous liquid and natural gas pipelines carrying product over long distances to users. 

PHMSA has estimated there are roughly 

2 million miles of distribution pipelines, most of which are intrastate 

pipelines. There are no hazardous liquid distribution pipelines.

4

However, there are transmission pipelines smaller than 12 inches in diameter and other 

pipelines that operate at pressures greater than 1440 psi. In addition, we have reported on 

safety regulations for certain transmission pipelines that operate at lower stress. For more 

information, see GAO, Safety Effects of Less Prescriptive Requirements for Low-Stress 

Natural Gas Transmission Pipelines Are Uncertain, GAO-12-389R (Washington, D.C.: 

Feb. 16, 2012).

5

However, some distribution pipelines can be as large as 24 inches in diameter and 

operate at higher pressures (i.e., over 350 psi). 
 

Page 4 GAO-12-388 Pipeline Safety 

Figure 1: Pipeline System

In recent years, shale oil and gas exploration and related development has 

led to the construction of new infrastructure, including gathering pipelines. 

Shale oil and gas refers to product that is trapped within underground shale 

formations; these fine-grain sedimentary rocks can be rich sources of oil 

and natural gas. Over the past decade, improvements in drilling 

technologies have allowed access to large volumes of shale oil and gas 

deposits in several states that were previously uneconomical to access.

In terms of fatalities and injuries, pipelines are the safest mode for 

transporting hazardous liquids and natural gas. From 2004 to 2010, there 

was an average of about 16 fatalities per year for all incidents reported to 

PHMSA.6

 

6In its regulations, PHMSA refers to the release of natural gas from a pipeline as an 

“incident” and a spill from a hazardous liquid pipeline as an “accident.” (49 CFR Part 195, 

Subpart B). For simplicity, this report will refer to both as “incidents.” PHMSA tracks 

summary level statistics for pipeline incidents that meet certain reporting criteria, such as 

those incidents resulting in a fatality. 

In comparison, in 2009, over 3,000 fatalities resulted from 

incidents involving large trucks carrying freight and about 700 additional 

fatalities resulted from freight railroad incidents. Yet, pipelines face a 

number of risks—such as corrosion and excavation damage—that can

damage the pipeline’s integrity and result in leaks and ruptures. A leak 

generally occurs with a slow release of product over a small area. A 

rupture involves the sometimes sudden development of a breach in the 

pipeline, which may cause hazardous liquids to spill or gas to spark and 
 

Page 5 GAO-12-388 Pipeline Safety 

ignite, resulting in an explosion.7

PHMSA administers the national regulatory program to ensure the safe 

transportation of hazardous liquid and gas by pipeline. PHMSA carries out 

its mission through regulation,

Such an incident occurred in San Bruno, 

California, on September 9, 2010, damaging or destroying over 100 

homes and killing 8 people.

8

In general, PHMSA performs its oversight role using uniform, minimum 

safety standards that all pipeline operators regulated by PHMSA must 

meet, as well as a supplemental risk-based regulatory program termed 

“integrity management” for pipelines in “high-consequence areas” where 

an incident would have greater consequences for public safety or the 

environment. The uniform, minimum safety standards include 

specifications for the design, construction, testing, inspection, operation, 

and maintenance of pipelines. For example, operators are required to 

install and maintain pipeline markers to clearly show a pipeline’s right-ofway. In addition, the risk-based integrity management programs for 

hazardous liquid and natural gas transmission pipelines and natural gas 

distribution pipelines require operators to systematically identify and 

mitigate risks to pipeline segments located in high-consequence areas, 

which are defined differently for three types of pipelines.

national consensus standards, research, 

education, inspections, and enforcement when safety problems or 

regulatory violations are found. The agency employs over 200 staff in its 

pipeline safety program, about half of whom inspect hazardous liquid and 

gas pipelines for compliance with safety regulations. Besides PHMSA, over 

300 state inspectors also help oversee pipelines and ensure safety.

• High-consequence areas for hazardous liquid pipelines include areas 

of highly populated areas, other populated areas, navigable 

waterways, and areas unusually sensitive to environmental damage.

• High-consequence areas for natural gas transmission pipelines 

include highly populated or frequently used areas, such as parks.

 

7

The risks and consequences posed by gas and hazardous liquids incidents also differ. 

Gas tends to ignite more easily, resulting in more explosions. Hazardous liquids ignite less 

easily, but can spill onto and pollute the environment. 

8Part 191 (Gas Reporting), Part 192 (Gas), Part 193 (Liquid Natural Gas), Part 194 (Liquid 

Facility Response Plans), and Part 195 (Hazardous Liquid) of Title 49 of the Code of 

Federal Regulations.
 

Page 6 GAO-12-388 Pipeline Safety 

• Most natural gas distribution pipelines would generally be considered 

to be in high-consequence areas, as defined under the transmission 

pipelines regulations, since they are typically located in highly 

populated areas.

PHMSA regulates hazardous liquid and natural gas gathering pipelines—

using uniform, minimum standards—based on their proximity to populated 

and environmentally sensitive areas. For natural gas gathering pipelines,9

Table 1: PHMSA Class Designations for Gas Pipelines 

PHMSA uses class locations—the same classification system used for 

natural gas transmission and distribution pipelines. (See table 1.) Under 

this system, PHMSA generally regulates onshore natural gas gathering 

pipelines in Class 2, 3, or 4 locations. For hazardous liquid gathering 

pipelines, PHMSA regulates those pipelines in incorporated and 

unincorporated cities, towns, and villages; pipeline segments that cross a 

waterway currently used for commercial navigation; and certain rural 

gathering pipelines within one-quarter mile of environmentally sensitive 

areas. This includes high-consequence areas, as defined for the 

hazardous liquid integrity management program. High-consequence 

areas can also be in Class 1, 2, 3, or 4 locations, which can entail 

different reporting requirements. For example, gathering pipeline 

operators in high-consequence areas that are in Class 1 locations are not 

required to report data on pipeline-related incidents, including fatality, 

injury, and property damage information.

Class 

designation Location features

Class 1 An offshore area or any location with 10 or fewer buildings intended for 

human occupancy within 220 yards of the centerline of the pipeline.

Class 2 Any location with more than 10 but fewer than 46 buildings intended for 

human occupancy within 220 yards of the centerline of the pipeline.

Class 3 Any location with more than 46 buildings intended for human occupancy 

within 220 yards of a pipeline, or an area where the pipeline lies within 

100 yards of either a building or a small, well-defined outside area (such 

as a playground) that is occupied by 20 or more persons at least 5 days 

a week for 10 weeks in any 12-month period.

Class 4 Any location where unit buildings with four or more stories above ground 

are prevalent.

Source: 49 C.F.R. § 192.5.

 

949 C.F.R. §192.5. 
 

Page 7 GAO-12-388 Pipeline Safety 

Under the current regulatory system, PHMSA does not regulate most 

gathering pipelines in the United States based on their location. For 

example, out of the more than 200,000 estimated miles of natural gas 

gathering pipelines, PHMSA regulates roughly 20,000 miles. Similarly, of 

the 30,000 to 40,000 estimated miles of hazardous liquid gathering 

pipelines, PHMSA regulates about 4,000 miles.10 However, according to 

PHMSA officials, the agency has the authority to collect data on all onshore 

hazardous liquid and gas gathering pipelines,11

Generally, PHMSA retains full responsibility for inspecting and enforcing 

regulations on interstate pipelines. However, states may be authorized to 

conduct inspections for interstate pipelines, as well as inspections and 

associated enforcement for intrastate pipelines. States can also 

promulgate regulations for intrastate pipelines, including gathering 

pipelines. PHMSA has arrangements with 48 states, the District of 

Columbia, and Puerto Rico to assist with overseeing interstate, intrastate, 

or both interstate and intrastate pipelines. These arrangements, in which 

states act as “agents” for PHMSA, can cover hazardous liquid pipelines 

only, gas pipelines only, or both (see fig. 2). State pipeline safety offices 

are allowed to issue regulations supplementing or extending federal 

regulations, but these state regulations must be at least as stringent as 

the minimum federal regulations. If a state wants to issue regulations that 

apply to pipelines that PHMSA does not regulate, such as unregulated 

gathering pipelines, it must do so under its own (state) authority.

even though it generally 

does not regulate gas gathering pipelines in Class 1 locations or hazardous 

liquid gathering pipelines not located in high-consequence areas.

 

10According to PHMSA officials, Alaska, California, Louisiana, and Oklahoma have the 

majority of federally unregulated gathering pipeline mileage in the United States. 

1149 U.S.C. §60102(b).This report refers to gathering pipelines that are not regulated by 

PHMSA but that PHMSA is not prohibited by law from regulating. Nonregulated gathering 

pipelines are typically unregulated Class 1 pipelines found in rural locations where there 

are no or low populations. 
 

Page 8 GAO-12-388 Pipeline Safety 

Figure 2: Interstate and Intrastate Agents for PHMSA
 

Page 9 GAO-12-388 Pipeline Safety 

While gathering pipelines generally pose lower safety risks than other 

types of pipelines, PHMSA does not collect comprehensive data on safety 

risks associated with gathering pipelines. In response to GAO’s survey, 

state pipeline safety agencies cited construction quality, maintenance 

practices, unknown or uncertain locations, and limited or no information 

on current pipeline integrity as safety risks for federally unregulated 

gathering pipelines.12

• Construction quality. Eighteen state agencies reported that the quality 

of installation procedures and construction materials is a moderate or 

high safety risk for unregulated gathering pipelines. The construction 

phase of pipeline installation is critical to ensure the long-term integrity 

of the pipeline because the installation methods and materials used in 

pipeline construction affect the pipeline’s resistance to deterioration 

over time. For example, one inspection requirement for regulated 

Operators of unregulated gathering pipelines are 

not required by federal law to report information on such risk factors. 

Consequently, federal and state pipeline safety officials do not know the 

extent to which individual operators collect such information and use it to 

monitor the safety of their pipelines. In our survey of 52 state agencies, 

39 agencies—10 monitoring hazardous liquid and 29 monitoring natural 

gas—responded that they had onshore gathering pipelines that PHMSA 

does not regulate located in their state. (See app. II for a summary of our 

survey results.) For these 39 agencies, four of the five top responses 

cited the following risk factors for onshore unregulated gathering pipelines 

as among the highest public safety risks.

 

12Risk is defined by PHMSA as the combination of the likelihood and the consequence of 

a specified hazard being realized. 

Limited Information 

on Safety Risks and 

Changing Operational 

Environments Are 

Leading PHMSA to 

Consider Collecting 

Data

Limited Information
 

Page 10 GAO-12-388 Pipeline Safety 

pipelines is that they may not be installed unless they have been 

visually inspected at the site of installation to ensure that they are not 

damaged in a manner that could impair their strength or reduce their 

serviceability.13

• Maintenance practices. Sixteen state agencies reported that the 

extent to which pipeline operators maintain their pipelines is a 

moderate or high safety risk for unregulated gathering pipelines. 

According to agency officials, after a pipeline is installed and 

operational, periodic maintenance—such as inspecting and testing 

equipment—is important to prevent leaks and ruptures and could 

extend the operating life of a pipeline. Furthermore, preventive 

measures and repairs conducted on unregulated gathering pipelines, 

as well as a record of such activities, could provide useful information 

on the safety and history of a given gathering pipeline.

This requirement does not currently apply to 

unregulated gathering pipelines.

• Location. Sixteen state agencies reported that the unknown or 

uncertain location of unregulated gathering pipelines presents a 

moderate or high safety risk. Although individual operators may know 

the locations of unregulated pipelines, state and local safety agencies 

may not know or may be uncertain about the locations and mileage of 

unregulated pipeline infrastructure in their communities. This 

information is particularly useful for “Call Before You Dig” programs 

operated by states and localities. If unregulated gathering pipelines 

are unmarked and program officials do not know the location of the 

pipelines, businesses and citizens may damage a pipeline during 

excavation, which could result in an incident—including fatalities, 

injuries, or damage to property or the environment—as well as the 

shutting down of the pipeline for repair.

• Pipeline integrity. Sixteen state agencies reported that not knowing or 

having limited knowledge about the integrity—the current condition—

of unregulated gathering pipelines is a moderate or high safety risk. 

Factors that affect the integrity of all pipelines—such as excavation 

damage and corrosion—also affect gathering pipelines. For example, 

excavation damage to a pipeline from nearby digging activities (see 

fig. 3) is the leading cause of pipeline incidents and, as previously 

noted, the uncertain location of unregulated gathering pipelines may 

 

1349 C.F.R. §195.206 (Hazardous Liquid) and 49 C.F.R. §192.307 (Gas).
 

Page 11 GAO-12-388 Pipeline Safety 

increase the potential for such damage. Furthermore, corrosion can 

occur on the inside and outside of metal pipelines and is not easily 

identified without appropriate pipeline assessments. From 2004 

through 2010, corrosion was reported as the cause of about 60 

percent—or nine incidents—of regulated gas gathering pipeline 

incidents. Generally, pipeline experts we spoke with said limited 

information on the integrity of unregulated gathering pipelines 

prevents analysis to assess the internal and external condition of 

these pipelines.

Figure 3: Excavation Damage

According to responses to our survey and interviews with industry officials 

and representatives, land-use changes and the increased extraction of oil 

and natural gas from shale deposits are two changes in the operating 

environments that could increase the safety risks for unregulated 

gathering pipelines.

• Land-use changes. The fifth top response reported by state pipeline 

safety agencies we surveyed was that increased urbanization has 

caused rural areas to become more densely populated and, in some 

cases, developments have encroached on existing pipeline rights-ofChanging Operational 

Environments
 

Page 12 GAO-12-388 Pipeline Safety 

way. (See fig. 4.) Nineteen state agencies reported land-use changes 

as a moderate or high risk for federally unregulated gathering 

pipelines. Federal and state pipeline safety officials we spoke with are 

concerned about the safety and proximity of people who work and live 

near pipeline rights-of-way. For example, one state official stated that 

although a new housing or business development can change a 

location’s designation from Class 1 to a higher class that would then 

fall under PHMSA’s jurisdiction, the operator may not be aware of the 

development and therefore would not monitor and apply more 

stringent regulations along that pipeline.

Figure 4: Changing Land Use around Pipelines

• Increased extraction of oil and gas from shale deposits. According to 

pipeline industry officials and representatives we interviewed, the 

increased extraction of oil and natural gas from shale deposits poses 

an increased risk to the public, partly because of the development of 

new and larger gathering pipeline infrastructure. Deposits of oil and 

natural gas have become increasingly important energy sources in the 

United States over the past decade (see fig. 5). According to the U.S. 

Energy Information Administration, shale gas accounted for 16 

percent of the total domestic natural gas supply in 2009 and is 

projected to increase to approximately 47 percent by 2035. This 

extraction has led to drilling and production in regions of the country 

that have previously seen little or no such activity. As a result of this 

ongoing activity, as well as future growth projections, state and federal 

safety officials we interviewed identified new gathering pipelines 

related to shale development as a potential public safety risk. The risk 
 

Page 13 GAO-12-388 Pipeline Safety 

is primarily due to the characteristics and quantity of pipeline 

infrastructure required to support this new production. Specifically, 

some of these new gathering pipelines have larger diameters and 

operate at higher pressures that are equivalent to traditional 

transmission pipelines, but without the regulatory requirements.14 For 

instance, an October 2010 report15

 

1449 C.F.R. § 195.452 (Hazardous Materials) & 49 C.F.R. Part 192 Subpart O (Gas). 

on pipeline issues and concerns in 

Fort Worth stated that some gathering pipelines were as large as 24 

inches in diameter with maximum allowable operating pressures 

similar to those for transmission pipelines. Those gathering pipelines 

were currently exempt from federal integrity management rules, which 

require some form of pipeline integrity assessment at least once every 

7 years, and clearly define how and when problems found during 

these assessments are to be reported and repaired.

15Accufacts Inc. and Pipeline Safety Trust, The State of Natural Gas Pipelines in Fort 

Worth, a special report prepared at the request of the Fort Worth League of 

Neighborhoods, Fort Worth, October 2010.
 

Page 14 GAO-12-388 Pipeline Safety 

Figure 5: Current and Prospective Shale Gas Regions

Note: This map depicts shale gas regions, where shale gas is known or thought to exist, but does not 

indicate where extraction is actually occurring. 

PHMSA officials stated that they are considering collecting data on 

federally unregulated onshore gathering pipelines to better understand 

and evaluate the safety risks posed by these pipelines. Although PHMSA 

has the legal authority to collect data on unregulated gathering pipelines, 

the agency is not required and has not yet exercised its authority to do so. 

PHMSA officials reported that, instead of collecting such data, the agency 

was focusing on the development of integrity management requirements 

PHMSA Is Considering 

Collecting Data
 

Page 15 GAO-12-388 Pipeline Safety 

and improved data collection for higher-risk transmission and distribution 

pipelines. However, PHMSA officials reported that there is value in having 

data for unregulated pipelines similar to what is currently collected on 

regulated pipelines, such as pipeline characteristics and reportable 

information on incidents—including the location, cause, and 

consequences of these incidents.

In addition, PHMSA issued Advanced Notices of Proposed Rulemakings 

(ANPRM) for onshore hazardous liquid and gas pipelines in October 2010 

and August 2011, respectively.16 For these proposed rulemakings, 

PHMSA has sought comment on, among other things, whether to extend 

regulation or other requirements to currently federally unregulated 

gathering pipelines. Concerning potential data collection, the ANPRMs 

sought comment on whether to require the submission of annual, 

incident, and safety-related condition reports on federally unregulated 

gathering pipelines, as well as on whether to establish a new, risk-based 

regime of safety requirements for large-diameter, high-pressure gas 

gathering pipelines, including those pipelines in rural locations.17

Currently, PHMSA collects annual, incident, and safety-related condition 

data on regulated pipelines. The specific types of safety-related data 

collected for regulated pipelines include the operator, pipeline system 

description, mileage by class location, diameter size, operating pressure, 

incident location, number of injuries and fatalities, property damage, and 

While 

the ANPRMs did not seek comment on exactly what new data to collect, 

PHMSA officials reported that the information would likely be similar to 

what is currently collected on regulated gathering pipelines and that they 

plan to issue final rules in late 2012. In the event that reporting 

requirements are adopted, PHMSA officials stated that gathering pipeline 

data would likely be collected on a state-by-state basis, which could later 

be expanded to the national level. However, PHMSA’s plans for collecting 

data are preliminary, and the extent to which PHMSA will collect data

sufficient to evaluate the potential safety risks associated with these 

pipelines is uncertain.

 

1675 Fed. Reg. 63774 (Oct. 18, 2010) and 76 Fed. Reg. 53086 (Aug. 25, 2011).

17PHMSA granted extensions to the comment period for both of these ANPRMs (see 76 

Fed. Reg. 303 (Jan. 4, 2011) and 76 Fed. Reg. 70953 (Nov. 16, 2011)). The ANPRM 

related to hazardous liquids closed for comment in February 2011 and the ANPRM for gas 

in January 2012.
 

Page 16 GAO-12-388 Pipeline Safety 

assessments conducted. These data help federal and state safety 

officials and pipeline operators increase the safety of these pipelines by 

better identifying and quantifying safety risks, as well as by implementing 

mitigation strategies, and addressing potential regulatory needs. It is for 

these same reasons that PHMSA, state, and some industry officials 

reported that collecting similar data for unregulated gathering pipelines 

would be beneficial. PHMSA officials also reported that in the event the 

agency started collecting data on unregulated onshore gathering 

pipelines, their current data reporting system could accommodate such a 

collection and not require large changes for regulators or operators. On 

the other hand, a few operators and industry groups we met with 

expressed concerns over the burden that new data reporting would 

represent. Before any potential data collection reporting requirements 

could be enacted, PHMSA and the Office of Management and Budget 

would review and evaluate the value of such information and associated 

burdens on industry. PHMSA officials said that while many operators 

should already have information on their gathering pipelines readily 

available, it would still be important to communicate with operators and 

take steps to minimize burdens in collecting new gathering pipeline data.

Some benefits of collecting such pipeline data can be seen through 

additional analysis of currently collected data. For example, PHMSA’s 

data on regulated pipelines indicate that more onshore reportable 

incidents, as well as total property damage, occur on transmission and 

distribution pipelines, than on regulated gathering pipelines (see figs. 6 

and 7). Although the number of reportable incidents for regulated gas 

gathering pipelines is lower than for other regulated pipelines, the value of 

total property damage increased in the past few years. In 2010, these 

reportable incidents accounted for, on average, about $1.8 million in 

property damage per incident.
 

Page 17 GAO-12-388 Pipeline Safety 

Figure 6: Number of Incidents for All Federally Regulated Pipeline Systems, 2004 

through 2010

Note: Regulated hazardous liquid data is not collected, segregated, and reported to PHMSA by type 

of pipeline (i.e., gathering and transmission). Also, there are no hazardous liquid distribution pipeline 

systems. Therefore, incident data for regulated hazardous liquid transmission and gathering pipelines 

is combined. 

Figure 7: Total Property Damage for All Regulated Pipeline Systems, 2004 through 

2010

Note: Regulated hazardous liquid data is not collected, segregated, and reported to PHMSA by type 

of pipeline (i.e., gathering and transmission). Also, there are no hazardous liquid distribution pipeline 

systems. Therefore, property damage data for regulated hazardous liquid transmission and gathering 

pipelines is combined.

Another benefit of collecting annual, incident, and safety-related condition 

pipeline data is an increased ability to assess and manage risks. We have 

previously reported on the importance of assessing and managing risks, 
 

Page 18 GAO-12-388 Pipeline Safety 

including quantifying those risks using data.18 Data are instrumental in 

quantifying risks and can reduce uncertainty in assumptions and policy 

judgments (e.g., safety threats and the likelihood that they will be 

realized).19 PHMSA officials reported that collecting data could help to 

determine the safety risks associated with federally unregulated gathering 

pipelines, such as tracking injuries, fatalities, and property damage for 

new gathering pipelines associated with shale development, and whether 

current safety regulations are appropriate. Related to whether current 

regulations are appropriate, Congress recently mandated that DOT 

review the sufficiency of existing federal and state laws and regulations to 

ensure the safety of hazardous liquid and gas gathering pipelines.20

Besides PHMSA, states may collect data on unregulated gathering 

pipelines, but the scope and nature of this data collection can vary. 

Although the federal government is responsible for setting minimum 

pipeline safety standards, states can adopt additional or stricter safety 

standards for intrastate pipeline facilities and transportation—including 

standards for data collection. For example, Texas’s state regulation 

further defined that the state’s safety jurisdiction for onshore gas 

gathering pipelines begins after the first point of measurement—where 

the product is first measured to determine the volume being extracted 

from the well—and is based on population, which is stricter than the 

Two 

industry associations reported that such data collection could help better 

ensure that federal pipeline programs are appropriately targeted at 

mitigating safety risks, cost-effective, and not unnecessarily broad in 

scope. Quantitatively assessing risks could also allow for a ranking and 

prioritizing of safety risks facing gathering pipelines in a manner that is 

currently not possible.

 

18GAO, Risk Management: Strengthening the Use of Risk Management Principles in 

Homeland Security, GAO-08-904T (Washington, D.C.: June 25, 2008).

19GAO, Homeland Security: DHS Risk-Based Grant Methodology Is Reasonable, But 

Current Version’s Measure of Vulnerability is Limited, GAO-08-852 (Washington, D.C.: 

June 27, 2008)

20Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011, Pub. L. No. 112-90, 

§21, 125 Stat. 1904, 1917 (2011).
 

Page 19 GAO-12-388 Pipeline Safety 

federal standard.21 Our survey revealed that only 3 of the 39 state 

agencies reported that they collect and analyze comprehensive pipeline 

spill and release data on federally unregulated pipelines. Such 

information can be used to help reduce future incidents. Additionally, the 

National Association of Pipeline Safety Representatives (NAPSR) 

recently conducted a nationwide survey22 to determine which state 

requirements match or exceed federal pipeline safety requirements. The 

survey reported that neither states nor the District of Columbia collected 

comprehensive data on federally unregulated gathering pipelines, as is 

required for federally regulated pipelines.

State pipeline safety agencies reported using five safety practices most 

frequently to help ensure the safety of onshore hazardous liquid and gas 

gathering pipelines not regulated by PHMSA, according to our survey of 

state agencies23 (see fig. 8). Several of these practices are designed to 

counter previously discussed safety risks; for example, implementing 

damage prevention programs can lower the risks of excavation damage.24

 

21Texas Administrative Code, Title 16, Part 1, Chapter 8 Subchapter A, Rule Section 8.5. 

Although the federal government is responsible for setting minimum pipeline safety 

standards, Texas, and other certified states, can adopt additional or more stringent safety 

standards for intrastate pipeline facilities and intrastate pipeline transportation. (49 U.S.C. 

§60104(c)). However, any intrastate safety standards adopted by Texas and other 

certified states must be compatible with the federal standards. 

Although these practices were cited most frequently, one-third or less of 

the state pipeline safety agencies with unregulated gathering pipelines 

use any one of these practices. For instance, 13 of the 39 state pipeline 

safety agencies with unregulated gathering pipelines in their state 

reported using the most frequently cited safety practice—damage 

22National Association of Pipeline Safety Representatives and the National Association of 

Regulatory Utility Commissioners, Compendium of State Pipeline Safety Requirements & 

Initiatives Providing Increased Public Safety Levels compared to Code of Federal 

Regulations, 1st Edition 2011 (Sept. 30, 2011).

23These practices refer to state pipeline safety practices that are more stringent than 

PHMSA’s regulatory requirements and to central activities, programs, or other policies that 

can help ensure the safety of various onshore pipelines. We recognize that in some states 

a practice may be part of the state’s regulations, while in other states, such practices are 

separate from regulations. 

24When we discuss safety practices, we refer to those safety practices that state agencies 

described as being relevant for helping ensure the safety of gathering pipelines. Some of 

these same practices may also be applied to other types of pipelines.

States Could Benefit 

from Sharing Safety 

Practices
 

Page 20 GAO-12-388 Pipeline Safety 

prevention programs. Additionally, some of the state agencies that 

reported using safety practices also responded that, overall, they had 

promulgated safety requirements for onshore gathering pipelines that 

were more stringent than those provided by PHMSA.

Figure 8: Most Frequently Used Safety Practices by States for Gathering Pipelines

• Damage prevention programs. Thirteen state agencies25

 

25When discussing the number of state agencies that reported using a given safety 

practice, these 13 agencies are a subset of the 39 state agencies that reported having 

unregulated gathering pipelines. 

reported that 

they implement and enforce a damage prevention program as a 

practice to help ensure pipeline safety. Damage prevention programs 

can help mitigate risks and increase safety through a number of 

activities. For example, damage prevention programs can help reduce 

the risk of excavation damage by encouraging citizens and other 

parties to collect information to help identify pipeline locations before 

digging begins. Damage prevention programs can also include 
 

Page 21 GAO-12-388 Pipeline Safety 

marking the rights-of-way for pipelines—including gathering 

pipelines—above ground to further reduce the likelihood of excavation 

damage (see fig. 9). States have developed or participated in damage 

prevention programs to help reduce instances of excavation damage, 

including damage to gathering pipelines. For example, Colorado has 

participated in the national One-Call program to reduce excavation 

damage. One-Call programs enable citizens and organizations to call 

an 811 number to notify utilities, pipeline operators, and others about 

the location and nature of planned digging. Utility, pipeline, or other 

organization members can then mark where underground pipelines 

run before any digging begins. Colorado pipeline safety officials 

reported that some calls related to the marking of regulated and 

unregulated gathering pipelines. As to the effectiveness of One-Call 

programs, the Common Ground Alliance has reported that, in 2010, 

when an excavator notified a call center before digging, damage 

occurred less than 1 percent of the time.26

 

26Common Ground Alliance, DIRT Annual Report for 2010 (Alexandria, VA, 2011). The 

Common Ground Alliance is an association dedicated to ensuring public safety, 

environmental protection, and the integrity of services by promoting effective damage 

prevention practices.
 

Page 22 GAO-12-388 Pipeline Safety 

Figure 9: Pipeline Marker

• Considering areas of highest risk. Ten state agencies reported they 

consider the areas of highest risk to effectively target resources as a 

safety practice. This approach can help address risks, such as 

corrosion and a lack of periodic maintenance, by directing oversight to 

those pipelines that could have the most serious consequences in the 

event of an incident.27

 

27While data are helpful for assessing risks, PHMSA and state agency officials mentioned 

using other information sources to qualitatively assess risks, such as guidance and 

protocols and general pipeline traits like location. 

In addition, considering the areas of highest 

risk could help address potential safety risks from new gathering 

pipeline infrastructure associated with shale development. For 

example, considering risk factors associated with larger pipelines, 

operating pressures, and location could help determine the actual 

risks posed by these new pipelines. Indeed, some of PHMSA’s more 

recent pipeline safety regulations addressing integrity management 

and high-consequence areas account for risk factors to help 
 

Page 23 GAO-12-388 Pipeline Safety 

determine which regulations might apply to a particular pipeline.28

Industry officials reported that it is more effective to target higher-risk 

areas than to allocate resources across all areas. Officials with the 

Texas Oil and Gas Association added that the risk of a pipeline 

incident in a heavily populated area warrants more attention than the 

risk of a similar incident in a sparsely populated area. This practice 

also acknowledges that gathering pipelines run through a wide variety 

of environments with varying risk levels (see fig. 10). Some states are 

overseeing pipelines based on identified safety risks. For example, 

safety compliance and enforcement staff at the Texas Railroad 

Commission29

 

28PHMSA’s integrity management program for transmission pipelines already requires 

operators to systematically manage risks to their pipelines in areas where an accident 

could have the highest consequences. In our past work on pipeline safety, we have 

supported the use of risk-based methodologies for PHMSA’s regulation of the pipeline 

industry. See GAO, Natural Gas Pipeline Safety: Risk-Based Standards Should Allow 

Operators to Better Tailor Reassessments to Pipeline Threats, 

reported that inspecting pipeline systems based on 

identified risks allows the state to inspect some pipelines less 

frequently, such as pipelines made from newer and safer materials, 

have advanced monitoring technology, or are located away from 

populations—like some rural gathering pipelines. Using these riskbased safety evaluations also enables Texas Railroad Commission 

inspectors to concentrate on higher-risk pipeline systems.

GAO-06-945 (Washington, 

D.C.: Sept. 8, 2006).

29Formed in 1891, the Texas Railroad Commission regulates the safety of intrastate 

natural gas pipelines and hazardous liquids pipelines in Texas. Commission staff conduct 

safety inspections of pipeline operators, issue compliance guidance, and enforce rules for 

Texas’s pipeline excavation damage prevention program. 
 

Page 24 GAO-12-388 Pipeline Safety 

Figure 10: Examples of Rural and Residential Gathering Pipeline Operational Environments near Dallas-Fort Worth

• Safety inspections. Nine state agencies reported they conduct 

recurring, scheduled, or unscheduled safety inspections of hazardous 

liquid and gas operators as another safety practice. NAPSR officials 

reported that safety inspections can be regularly scheduled 

inspections, during which inspectors check system components,

specialized inspections (i.e., integrity management) aimed at higherrisk areas, or random checks. These inspections can also help 
 

Page 25 GAO-12-388 Pipeline Safety 

address risks related to the installation and construction quality of a 

pipeline by ensuring that the pipeline is structurally sound and shows 

no evidence of questionable materials or other problems, such as 

corrosion and excavation damage. PHMSA has recommended that 

state pipeline safety agencies perform periodic surprise inspections 

on new pipeline construction to determine whether operators are 

complying with construction requirements. Inspectors with the Texas 

Railroad Commission, in addition to sampling on-site pipeline facilities 

in the field, also review pipeline operators’ records and documentation 

on selected pipeline systems for compliance with federal and state 

pipeline safety regulations. These risk-based safety evaluations have 

included the construction of gathering pipelines related to shale 

development and pipelines not regulated by PHMSA. Such 

evaluations also help ensure that operators maintain an up-to-date 

and consistent document records system for installation, operations, 

and emergency response (see fig. 11).

Figure 11: Gathering Pipeline Construction Documentation in Texas
 

Page 26 GAO-12-388 Pipeline Safety 

• Public outreach and communication. Seven state agencies reported 

they engage in outreach or other communication with communities and 

citizens to boost awareness and knowledge of pipeline safety practices 

they use. The Common Ground Alliance has reported on the 

importance of outreach, including the use of structured education 

programs, targeted mailings, and paid advertising. These and other 

outreach methods can also underscore the importance of other safety 

practices, such as damage prevention and One-Call programs. These 

outreach efforts can involve a number of methods and include 

educating and engaging the public. In Colorado, Damage Prevention 

Councils have hosted monthly meetings and participated in local 

community events—such as educational seminars, parades, and trade 

shows—to help educate citizens on pipeline safety. Another Colorado 

entity active in damage prevention is the Colorado Pipeline Association, 

which comprises pipeline operators dedicated to promoting pipeline 

safety by providing information for excavators, state residents, 

businesses, emergency responders, and public officials. In one 

community, according to a PHMSA official, citizens viewed state safety 

officials as an objective and neutral party that provided information and 

perspectives on the planned construction of gathering pipelines. In 

tandem with private operators, the state officials were able to answer 

citizen questions and address concerns.

• Enforcement. Six state agencies reported a safety practice of 

establishing a system of escalated enforcement to enhance and 

increase regulatory attention on operators that have experienced 

incidents. A pipeline expert we interviewed said that promoting an 

effective enforcement program was necessary to help ensure pipeline 

safety. A system of escalated enforcement can enhance and increase 

regulatory attention on pipeline operators with safety violations. One 

state pipeline safety official reported that making such attention public 

can bring additional pressure on and provide incentives for a company 

to maintain and operate its infrastructure safely. One PHMSA official 

reported that although many states do not have an enforcement 

program as elaborate as PHMSA, states with stronger enforcement 

programs have more of an impact on the operators to increase safety. 

Pipeline operators may have procedures and established contacts 

with local enforcement personnel in order to act appropriately to halt 

dangerous excavation activities that may damage pipelines and 

potentially cause an immediate threat to life or property. Regarding 

federally unregulated gathering pipelines, one Colorado official 

reported that because gathering pipeline companies operate pipelines 

and conduct excavation work, they would be subject to any necessary 

enforcement due to safety violations.
 

Page 27 GAO-12-388 Pipeline Safety 

However, sharing of information among states on the safety practices they 

use for unregulated gathering pipelines appears to be limited. Some state 

and PHMSA officials we interviewed had limited awareness of what other 

states were doing to help ensure the safety of gathering pipelines not 

regulated by PHMSA. For example, pipeline safety officials we interviewed 

had limited awareness of other state programs—sometimes even for an 

adjacent state—even if those programs were intended to address common 

risks, such as reducing excavation damage and corrosion. PHMSA officials 

were likewise unable to report on the safety practices that many states use 

or on states’ regulations that were more stringent than federal 

requirements. PHMSA’s website holds a wealth of information on various 

pipeline safety topics, including recent pipeline forums and industry 

research, incident investigations, and other information. However, 

information targeted at gathering pipelines, including relevant safety 

practices and state activities, is limited.30

Increased communication and information sharing about pipeline safety 

practices could boost the use of those practices in states with unregulated 

gathering pipelines. As previously discussed, even the safety practice that 

our survey respondents reported using most frequently—implementing a 

damage prevention program—was used by just 13 of the 39 responding 

state pipeline safety agencies with unregulated gathering pipelines in their 

In addition, all related information 

could be grouped to decrease time spent searching and scanning. 

Currently, there is no central PHMSA web page or resource for gathering 

pipelines, regulated or unregulated—possibly due, in part, to the lower 

safety risks that regulated gathering pipelines have posed to people and 

property when compared with other pipelines, like transmission pipelines. 

PHMSA officials said that its website also focuses on pipelines that 

PHMSA regulates but excludes most gathering pipelines. PHMSA has

considered the development of a website to help facilitate sharing 

information among states. While this project is still in the planning stages 

and not targeted at gathering pipelines, it could be a resource to share 

program and safety practices among states and PHMSA.

 

30Websites that are limited tend to be less usable. Usable websites—that is, those that are 

planned and designed to collect data on what users need and include various usercentered design methods, among other things—ensure that needed information is 

available and clearly displayed. These standards are based on guidance posted on the 

U.S. Department of Health and Human Services’ websites, http://www.usability.gov, a 

source for information on usability and user-centered design. It provides guidance and 

tools on how to make websites and other communication systems more usable and 

useful. 
 

Page 28 GAO-12-388 Pipeline Safety 

state. The other four safety practices cited are reportedly used even less. 

Improved information sharing among states and PHMSA could help 

spread information on how these safety practices—which are also used 

for regulated pipelines–-could be applied to unregulated gathering 

pipelines, thereby benefiting other states with unregulated gathering 

pipelines. We have previously reported on the value of organizations 

reporting and sharing safety information as part of encouraging a wider 

safety culture.31 Safety culture can include organizational awareness of 

safety and open communication. The benefits of a strong safety culture 

have widespread applicability, including in other transportation areas—

such as aviation and transit. PHMSA could serve to facilitate feedback 

and evaluate safety information related to unregulated gathering pipelines 

in states. By collecting information on safety practices and other 

information relevant to unregulated gathering pipelines, PHMSA could 

increase the potential for identifying systemic issues, disseminating 

lessons learned, and improving pipeline safety across the country. 

PHMSA officials reported that, in the past, similar online and educational 

efforts in other areas have resulted in increasing education and 

information sharing among state pipeline safety officials.

While the safety risks of federally unregulated, onshore hazardous liquid 

and gas gathering pipelines are generally considered to be lower than 

other types of pipelines, PHMSA is currently not able to determine the 

performance and safety of these gathering pipelines because it does not 

collect the necessary pipeline operator data. The agency is considering 

options to collect such information, which could facilitate quantitatively 

assessing the safety risks posed by unregulated gathering pipelines. 

Furthermore, these data would be critical in helping PHMSA to evaluate 

the sufficiency of safety regulations for gathering pipelines as required by 

the congressional mandate or that increasing shale development across 

the country might necessitate. Making data-driven, evidence-based 

decisions about the risks of federally unregulated gathering pipelines is 

especially important in a time of limited resources.

The absence of an information-sharing resource focused on federally 

unregulated gathering pipelines means that both states and PHMSA 

 

31GAO, Rail Transit: FTA Programs Are Helping Address Transit Agencies’ Safety 

Challenges, but Improved Performance Goals and Measures Could Better Focus Efforts, 

GAO-11-199 (Washington, D.C.: Jan. 31, 2011). 

Conclusions
 

Page 29 GAO-12-388 Pipeline Safety 

could miss opportunities to share lessons learned and successful 

practices for helping to ensure pipeline safety. Sharing such lessons and 

related safety reporting can help support a safety culture and increase 

state officials’ awareness of possible safety practices or strategies that 

they can use to enhance pipeline safety. Lessons learned can also help 

states avoid the mistakes of others. Additionally, increased information 

sharing through such a resource would help PHMSA become more aware 

of state pipeline safety practices and initiatives—which in turn would 

assist PHMSA in sharing and supporting these safety practices, as well 

as in considering what state efforts may have applicability for federal 

programs, regulation, and guidance.

To enhance the safety of unregulated onshore hazardous liquid and gas 

gathering pipelines, we recommend that the Secretary of Transportation 

direct the PHMSA Administrator to take the following two actions:

• Collect data from operators of federally unregulated onshore 

hazardous liquid and gas gathering pipelines, subsequent to an 

analysis of the benefits and industry burdens associated with such 

data collection. Data collected should be comparable to what PHMSA 

collects annually from operators of regulated gathering pipelines (e.g., 

fatalities, injuries, property damage, location, mileage, size, operating 

pressure, maintenance history, and the causes of incidents and 

consequences).

• Establish an online clearinghouse or other resource for states to share 

information on practices that can help ensure the safety of federally 

unregulated onshore hazardous liquid and gas gathering pipelines. 

This resource could include updates on related PHMSA and industry 

initiatives, guidance, related PHMSA rulemakings, and other 

information collected or shared by states.

Recommendations for 

Executive Action
 

Page 30 GAO-12-388 Pipeline Safety 

We provided the Department of Transportation with a draft of this report 

for review and comment. The department provided technical corrections, 

which we incorporated as appropriate.

We are sending copies of this report to interested congressional 

committees and the Secretary of Transportation. In addition, the report is 

available at no charge on the GAO website at http://www.gao.gov. 

If you or your staff have any questions about this report, please contact 

me at (202) 512-2834 or flemings@gao.gov. Contact points for our 

Offices of Congressional Relations and Public Affairs may be found on 

the last page of this report. GAO staff who made major contributions to 

this report are listed in appendix III.

Susan A. Fleming

Director

Physical Infrastructure Issues

Agency Comments
Appendix I: Objectives, Scope, and 

Methodology

Page 31 GAO-12-388 Pipeline Safety 

The objectives of our review were to determine (1) the safety risks that 

exist, if any, with onshore hazardous liquid and natural gas gathering 

pipelines that are not currently under the Pipeline and Hazardous 

Materials Safety Administration (PHMSA) regulation and (2) the practices 

states are using to help ensure the safety of unregulated onshore 

gathering pipelines. To address our objectives, we reviewed PHMSA and 

other federal agency regulations, as well as available safety data on 

regulated pipelines. We also interviewed officials at PHMSA, state 

pipeline safety agencies, pipeline companies and other industry 

stakeholders, and related associations. We obtained data on pipelines 

regulated by PHMSA to understand the types of pipeline data currently 

collected, as well as to compare and analyze accident, injury, fatality, and 

other trends. We reviewed the data and conducted follow-up work as 

necessary to determine that the data were complete, reasonable, and 

sufficiently reliable for the purposes of this report. We also conducted site 

visits—selecting locations based on geography, pipeline infrastructure, 

and other factors—to interview pipeline officials and representatives in 

Denver, Pittsburgh, and Dallas-Fort Worth. We later identified an initial list 

of safety risks and safety practices through information collection and 

document review processes.

To determine what safety risks may be associated with federally 

unregulated gathering pipelines—in addition to reviewing federal agency 

regulations, regulated pipeline safety data, and conducting various 

interviews—and because of the lack of historical and nationwide data, we 

developed and administered a web-based survey to state pipeline safety 

agencies in all 50 states and the District of Columbia.1

 

1Alaska and Hawaii have chosen not to participate in pipeline arrangements with PHMSA. 

Therefore, a PHMSA official who conducts state pipeline safety inspections in these states 

responded to those states’ surveys. 

Our survey was 

intended to collect information otherwise not available from PHMSA, 

states, industry, or other sources on safety risks associated with onshore, 

federally unregulated hazardous liquid and gas gathering pipelines and 

related safety practices to help address those risks and ensure safety.

We used the survey to identify which states had unregulated, onshore 

gathering pipelines and what perceived pipeline safety risks were 

associated with those pipelines. To identify safety practices states are 

using, we reviewed industry documents and conducted interviews with 

public and private experts and officials. Then, as part of our survey of 

state pipeline safety agencies, we asked officials to identify the practices 

Appendix I: Objectives, Scope, and 

Methodology 
Appendix I: Objectives, Scope, and 

Methodology

Page 32 GAO-12-388 Pipeline Safety 

they used to ensure the safety of onshore, federally unregulated 

hazardous liquid and gas gathering pipelines. From our survey results, we 

identified the most frequently cited safety practices, including additional 

state programs, activities, and other practices.

To develop the survey questions, we conducted initial interviews with 

state officials and other pipeline safety stakeholders to identify safety 

issues regarding unregulated gathering pipelines. We also reviewed key 

literature to ascertain pipeline safety practices and other issues. We 

consulted with PHMSA officials and reviewed PHMSA documentation to 

identify the proper terminology for use in the survey.

The survey was pretested with potential respondents from state pipeline 

safety agencies, as well as with the Congressional Research Service and 

National Association of Pipeline Safety Representatives.2

The survey was conducted using self-administered electronic 

questionnaires posted on the World Wide Web. We sent e-mail 

notifications to 52 agencies responding to our survey. We also e-mailed 

We did this to 

ensure that (1) the questions were clear and unambiguous, (2) the terms 

we used were precise, (3) the survey did not place an undue burden on 

the agency officials completing it, and (4) the survey was independent 

and unbiased. In addition, the survey was reviewed by an internal, 

independent survey expert. We took steps in survey design, data 

collection, and analysis to minimize nonsampling errors. For example, we 

worked with PHMSA officials to identify the appropriate survey 

respondents—state pipeline safety agencies. To minimize measurement 

error that might occur from respondents interpreting our questions 

differently from our intended purpose, we extensively pretested the 

survey and followed up with nonresponding units and with units whose 

responses violated certain validity checks. We identified only two cases 

where the respondents had slightly varied responses from our intended 

question, although the majority understood our questions as intended. 

Finally, to eliminate data-processing errors, we independently verified the 

computer program that generated the survey results. Our results are not 

subject to sampling error because we administered our survey to all 50 

state pipeline safety agencies and the District of Columbia.

 

2The National Association of Pipeline Safety Representatives is a national association 

representing the state pipeline safety inspectors in the contiguous United States, as well 

as the District of Columbia and Puerto Rico. 
Appendix I: Objectives, Scope, and 

Methodology

Page 33 GAO-12-388 Pipeline Safety 

each potential respondent a unique password and username to ensure 

that only members of the target population could participate in the survey. 

To encourage respondents to complete the survey, we sent an e-mail 

reminder to each nonrespondent about 2 weeks after our initial e-mail 

message. The survey data were collected from July through September 

2011. We received responses from all 50 states and the District of 

Columbia, for an overall response rate of 100 percent. This “collective 

perspective” obtained from each of the agencies helps to mitigate 

individual respondent bias by aggregating information across the range of 

different viewpoints. For purposes of characterizing the results of our 

survey, we identified specific meanings for the words we used to quantify 

the results, as follows: “a few” means between 1 percent and 24 percent 

of respondents, “some” means between 25 percent and 44 percent of 

respondents, “about half” means between 45 percent and 55 percent of 

respondents, “a majority” means between 56 percent and 74 percent of 

respondents, “most” means between 75 percent and 94 percent of 

respondents, and “nearly all” means 95 percent or more of respondents. 

This report contains the central results from the survey (see app. II).

We conducted this performance audit from February 2011 to March 2012 

in accordance with generally accepted government auditing standards. 

Those standards require that we plan and perform the audit to obtain 

sufficient, appropriate evidence to provide a reasonable basis for our 

findings and conclusions based on our audit objectives. We believe that 

the evidence obtained provides a reasonable basis for our findings and 

conclusions based on our audit objectives.
Appendix II: Summary Results, GAO Pipeline 

Safety Regulations Survey 

Page 34 GAO-12-388 Pipeline Safety 

General Pipeline Safety Regulation Survey Questions Hazardous Liquid Natural Gas

YES RESPONSES Frequency Frequency

Does your state have any onshore gathering pipelines outside of high consequence areas that 

PHMSA does not regulate?

10 29

Does your agency collect any data for onshore gathering pipelines that PHMSA does not 

regulate?

4 7 

Does your state have safety requirements for onshore gathering pipelines that are more 

stringent than those provided by PHMSA?

1 7 

Subpopulation Total 18 52

How great a safety risk, if at all, are the following factors for onshore hazardous liquid 

and gas gathering pipelines in your state that PHMSA does not regulate? Hazardous Liquid Natural Gas

MODERATE AND HIGH SAFETY RISK RESPONSES Frequency Frequency

A. Limited or no annual reporting data (similar to PHMSA’s) available on these pipelines (e.g., 

mileage, leaks)

1 9 

B. Limited or no incident data available on these pipelines (e.g., spills, releases) 2 11

C. Limited or no information on the integrity of these pipelinesa 2 13

D. Unknown or uncertain locations of pipelines 3 13

E. Location of these pipelines in high consequence areasb 4 15

F. Limited or no inspections conducted on these pipelinesa 3 13

G. Limited or no information on the pipe size 2 7 

H. Limited or no information on operating pressurea 3 13

I. Installation/construction quality 3 15

J. Periodic maintenance not conducted on these pipelines 3 13

K. Quality of product (sour or non-sour, corrosive, abrasive, etc.) 3 11

L. Limited information on reporting damages 2 9 

M. Other (Please specify) 1 1 

Subpopulation Total 10 29

a

This response category was combined to represent an overall category of “Limited or no information 

of the pipeline integrity.” 

b

A survey follow up found that the majority of respondents also understood the question as it was 

intended to mean Class 1 unregulated gathering pipelines previously located in rural areas that may 

have transitioned to be located in either (Class 2, 3 or 4) high consequence areas due to changing 

land use. 

Appendix II: Summary Results, GAO Pipeline 

Safety Regulations Survey
Appendix II: Summary Results, GAO Pipeline 

Safety Regulations Survey

Page 35 GAO-12-388 Pipeline Safety 

Does your agency use any of the following practices to 

ensure onshore hazardous liquid and gas pipeline safety 

in your state? Hazardous Liquid Natural Gas

Regulated 

Pipelines

Unregulated 

Gathering

Regulated 

Pipelines

Unregulated 

Gathering

YES RESPONSES Frequency Frequency Frequency Frequency

A. Considering the areas of highest risk to effectively target 

resources

14 3 47 7 

B. Collecting and analyzing comprehensive pipeline spill/ 

release data on various types of pipelines

6 1 27 2 

C. Standardizing spill/ release data collection in order to 

better assess trends or common causes of spills/ releases so 

that prevention measures can be targeted and evaluated to 

reduce future incidents

5 1 22 2 

D. Engaging in outreach or other communication with 

communities and citizens to boost awareness or knowledge 

of pipelines, including their locations

10 3 37 4 

E. Coordinating with operators to understand new 

technologies, including computer software, pipeline inspection 

devices, and other tools to report on pipelines

11 2 34 2 

F. Using existing or emerging technologies to reduce the time 

required to detect pipeline leaks

8 1 21 3 

G. Working to increase construction quality to ensure a long 

life for pipeline infrastructure

11 2 40 3 

H. Prioritizing the replacement or repair of aging or otherwise 

limited infrastructure 

9 1 37 2 

I. Conducting recurring, scheduled or unscheduled safety 

inspections of operators

14 3 47 6 

J. Establishing a system of escalated enforcement to 

enhance and increase regulatory attention on operators that 

have spills/ releases

11 2 29 4 

K. Developing standards or other bench marks to measure 

and evaluate performance in encouraging safety

7 2 28 2 

L. Monitoring implementation of corrective or preventive 

measures to evaluate their impact or effectiveness

13 0 40 4 

M. Using existing integrity management practices for PHMSA 

unregulated lines

8 2 15 2 

N. Implementing and enforcing a damage prevention program 13 3 38 10

O. Other (Please specify) 0 1 7 2 

Subpopulation Total 18 10 52 29

Source: GAO.
Appendix III: GAO Contact and Staff 

Acknowledgments

Page 36 GAO-12-388 Pipeline Safety 

Susan A. Fleming, (202) 512-2834 or flemings@gao.gov

In addition to the contact named above, other key contributors to this 

report were Sara Vermillion (Assistant Director), Matt Cail (Analyst-inCharge), Aisha Cabrer, David Hooper, Stuart Kaufman, Josh Ormond, 

Jerome Sandau, Jeremy Sebest, Rebecca Shea, Don Watson, and 

Adam Yu.

Appendix III: GAO Contact and Staff 

Acknowledgments 

GAO Contact

Staff 

Acknowledgments

(541077)
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