# Pipeline Transportation Emergencies

- **operation:** document
- **citation:** ERG 2024, Pipeline Transportation Emergencies
- **title:** Pipeline Transportation Emergencies
- **source type:** guidance
- **agency:** U.S. DOT / Transport Canada / SICT
- **status:** guidance
- **official:** true
- **published on:** 2024-04-04
- **effective on:** Not available
- **summary:** Official ERG2024 pipeline transportation emergencies guidance, pages 24-29.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-erg-2024-pipeline-transportation.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-erg-2024-pipeline-transportation.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-erg-2024-pipeline-transportation
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2024-04/ERG2024-Eng-Web-a.pdf#page=24
**body:**

PIPELINE TRANSPORTATION
In North America, hazardous materials/dangerous goods are commonly transported through
millions of miles of pipelines and related structures. Products transported include natural gas,
natural gas liquids, crude oil, gasoline, diesel fuel, anhydrous ammonia, carbon dioxide, jet
fuel, and other commodities. Although most pipelines are buried, often there are above‑ground
structures and markers indicating the presence of pipelines. First responders should be
aware of the pipelines in their jurisdictions, the products they transport, and the operators
responsible for those pipelines. Proactive relationships can be beneficial in the safe and
effective management of pipeline emergencies.
Types of Pipelines
Natural Gas Pipelines
Natural Gas Transmission Pipelines
Large-diameter, steel pipelines transport flammable natural gas (toxic and non-toxic) at
very high pressures ranging from 200 to 1,500 psi*. Natural gas in transmission pipelines is
odorless — generally not odorized with mercaptan (the “rotten egg” smell); however, natural
gas containing hydrogen sulfide (H2S) will have a distinct “rotten egg” odor.
Natural Gas Distribution Pipelines
Natural gas is delivered directly to customers via distribution pipelines. These pipelines are
typically smaller-diameter, lower-pressure pipelines constructed of steel, plastic, or cast iron.
Natural gas in distribution pipelines is odorized with mercaptan (the “rotten egg” smell).
Natural Gas-Gathering and Natural Gas Well Production Pipelines
Natural gas-gathering/well production pipelines collect “raw” natural gas from wellheads and
transport the product to gas-processing and/or gas-treating plants. These gathering pipelines
carry natural gas mixed with some quantity of natural gas liquids, water, and, in some areas,
contaminants such as toxic hydrogen sulfide (H2S). Natural gas in these pipelines is not
odorized with mercaptan (the “rotten egg” smell); however, natural gas that contains hydrogen
sulfide (H2S) will have a distinct “rotten egg” odor.
Hazardous Liquid and Highly Volatile Liquid Pipelines
Hazardous Liquid Pipelines
Crude oil, refined petroleum products (e.g. gasoline, kerosene, jet fuel or diesel) and hazardous
liquids (e.g. anhydrous ammonia or ethanol) are often transported by pipelines.
Many liquid petroleum pipelines transport different types of liquid petroleum in the same
pipeline. To do so, the pipeline operator sends different products in “batches.” For example,
an operator could send gasoline for several hours, and then switch to jet fuels, before
switching to diesel fuel.
* Data from http://naturalgas.org/naturalgas/transport/
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Highly Volatile Liquid (HVL) Pipelines
HVL pipelines transport hazardous liquids which will form a vapor cloud when released to
the atmosphere and which have a vapor pressure exceeding 276 KPa (40 psia) at 37.8°C
(100°F). An example of an HVL is liquid propane.
Pipeline Markers
Since pipelines are usually buried underground, pipeline markers are used to indicate their
presence in an area along the pipeline route. Of the three types of pipelines typically buried
underground — distribution, gathering, and transmission — only transmission pipelines are
marked with the following above-ground markers used to indicate their route.
Markers warn that a transmission pipeline is located in the area, identify the product
transported in the line, and provide the name and telephone number of the pipeline operator
to call. Markers and warning signs are located at frequent intervals along natural gas and
liquid transmission pipeline rights-of-way, and are located at prominent points such as where
pipelines intersect streets, highways, railways, or waterways.
Pipeline markers only indicate the presence of a pipeline—they do not indicate the exact
location of the pipeline. Pipeline locations within a right-of-way may vary along its length and
there may be multiple pipelines located in the same right-of-way.
NOTE:
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Markers for pipelines transporting materials containing dangerous levels of hydrogen
sulfide (H2S) may have markers that say: “Sour” or “Poison.”
Natural gas distribution pipelines are not marked with above-ground signs.
Gathering/production pipelines are often not marked with above-ground signs.
Page 23

Pipeline Structures (Above Ground)
Natural Gas Transmission Pipelines: Compressor stations, valves, metering stations.
Natural Gas Distribution Pipelines: Regulator stations, customer meters and
regulators, valve box covers.
Natural Gas Gathering/Well
Production Pipelines:
Petroleum and Hazardous
Liquids Pipelines:
Compressor stations, valves, metering stations,
wellheads, piping, manifolds.
Storage tanks, valves, pump stations,
loading racks.
Indications of Pipeline Leaks and Ruptures
Pipeline releases can range from relatively minor leaks to catastrophic ruptures. It is important
to remember that gases and liquids behave differently once they are released from a pipeline.
Generally, the following could be indications of a pipeline leak or rupture:
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Hissing, roaring, or explosive sound
Flames appearing from the ground or water (perhaps very large flames)
Vapor cloud/fog/mist
Dirt/debris/water blowing out of the ground
Liquids bubbling up from the ground or bubbling in water
Distinctive, unusually strong odor of rotten eggs, mercaptan (an odorant in some
natural gas pipelines), skunk, or petroleum
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Discolored/dead vegetation or discolored snow above a pipeline right-of-way
Oil slick or sheen on flowing/standing water
An area of frozen ground in the summer
An unusual area of melted snow in the winter
Page 24

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General Considerations for Responding to a Pipeline Emergency
Safety First! Your safety and the safety of the community you protect is top priority.
Remember to approach a pipeline incident from upwind, uphill, and upstream while using
air monitoring equipment to detect for the presence of explosive and/or toxic levels of
hazardous materials/dangerous goods.
– Always wear proper personal protective equipment. Be prepared for a flash fire. Use
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shielding to protect first responders in the event of an explosion. Use respiratory
protection.
– Never operate pipeline valves (except in coordination with the pipeline operator);
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this could make the incident worse and put you and others in danger.
– Never attempt to extinguish a pipeline fire before supply is shut off; this could result
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in the accumulation of a large flammable/explosive vapor cloud or liquid pool that
could make the incident worse and put you and others in danger.
– Do not walk or drive into a vapor cloud in an attempt to identify the product(s)
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involved.
– Do not park over manholes or storm drains.
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– Do not approach the scene with vehicles or mechanical equipment until the isolation
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zones have been established (vehicles are a potential ignition source).
Secure the site and determine a plan to evacuate or shelter-in-place. Work with other
responders to deny entry to an area.
Identify the product and the operator. If safe to do so, you may be able to identify the
product based on its characteristics or other external clues. Look for pipeline markers
indicating the product, operator of the pipeline, and their emergency contact information.
Pipelines transport many different types of products, including gases, liquids, and highly
volatile liquids that are in a liquid state inside the pipeline but in a gaseous state if
released from the pipeline. The vapor density of gases determines if they rise or sink in
air. Viscosity and specific gravity also are important characteristics of hazardous liquids
to consider. Identification of the product also will help you determine the appropriate
distance for isolation of the affected area.
Notify the pipeline operator using the emergency contact information on the pipeline
marker or other contact information you may have received from the pipeline operator.
The pipeline operator will be a resource to you in the response.
Establish a command post. Implement the Incident Command Structure, as needed,
and be prepared to implement a Unified Command as additional stakeholders and
resources arrive.
Page 25

Other Important Considerations
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If no flames are present, do not introduce ignition sources such as open flames, running
vehicles, or electrical equipment (cell phones, pagers, two-way radios, lights, garage
door openers, fans, door bells, etc.).
Abandon any equipment used in or near the area of the pipeline release.
If there is no risk to your safety or the safety of others, move far enough away from any
noise coming from the pipeline to allow for normal conversation.
Pipelines often are close to other public utilities, railroads, and highways; these can be
impacted by pipeline releases or may be potential ignition sources.
Natural gas can migrate underground from the source of a release to other areas via the
path of least resistance (including through sewers, water lines, and geologic formations).
Considerations for Establishing Protective Action Distances
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Type of product
– If you know the material involved, identify the three-digit guide number by looking
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up the name in the alphabetical list (blue section). The relevant guide will provide
an idea of the risks posed by the material.
Pressure and diameter of pipe (the pipeline operator can tell you this if you don’t
already know it)
Timing of valve closure by the pipeline operator (quickly for automated valves; longer
for manually operated valves)
Dissipation time of the product in the pipeline once valves are closed
Ability to conduct atmospheric monitoring and/or air sampling
Weather (wind direction, etc.)
Local variables such as topography, population density, demographics, and fire
suppression methods available
Nearby building construction material/density
Natural and man-made barriers (such as highways, railroads, rivers, etc.)
Page 26

U.S. Pipeline Resources
U.S. Pipeline Locations: The National Pipeline Mapping System (NPMS)
https://www.npms.phmsa.dot.gov indicates the general locations of hazardous liquids and
natural gas transmission pipelines found within the U.S. The pipelines depicted in the NPMS
are within 500 feet of their actual locations. Emergency responders may apply for an NPMS
web viewer account that will allow access to more detailed information than is available to the
general public. The NPMS does not contain gathering/production or natural gas distribution
pipelines.
U.S. Pipeline Emergency Response Training: Where appropriate, reference pipeline
emergencies training materials produced by the Pipeline and Hazardous Materials Safety
Administration. Your state or jurisdiction also may provide training on how to handle the
response to a pipeline incident.
Other Resources:
Pipeline Association for Public Awareness
https://www.pipelineawareness.org/
U.S. DOT, Pipeline and Hazardous Materials Safety Administration
https://www.phmsa.dot.gov/safety-awareness/pipeline/safety-awareness-overview
Pipeline Emergency Responders Initiative (PERI)
https://www.phmsa.dot.gov/pipeline/peri/pipeline-emergency-responders-initiative-peri
Canadian Pipeline Resources
For more information about pipelines in Canada, please consult the Canada Energy
Regulator website:
https://www.cer-rec.gc.ca/en/index.html
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