Maintaining the Fitness of Enbridge’s Systems

Safety is not just a core value at Enbridge. It’s the very foundation of our business. We work relentlessly to ensure the safety of our workforce and communities, keep our infrastructure healthy and fit for service, and maintain strong emergency preparedness and response systems.

Everything we do at Enbridge begins with safe and reliable operations to keep our energy infrastructure healthy and fit for service. Our goal, always, is to lead our industry in safety and reliability.

Business Context and our Strategic Response

Enbridge’s integrity management program addresses all aspects of evaluating and maintaining asset integrity to minimize risks and consequences. We take a lifecycle view of integrity management, encompassing design and construction, monitoring and prevention, leak detection and community outreach and engagement.

Maintaining and continually improving upon safe, reliable performance requires us to not only diligently inspect our pipelines and facilities to ensure fitness for service; we must also learn from past incidents and near misses so we continually strengthen the system of barriers and controls that will prevent leaks and releases.

We are disappointed when we experience any incident—of any magnitude. Our goal is clear: to prevent all injuries, occupational illnesses and incidents. We investigate each event to identify and address root causes. The learnings from incidents, research and reviews feed back into our management system, our operating procedures and the conversations we have with our employees about maintaining an accountable, vigilant and resilient safety culture.

Our Approach

We invest in tools, technology and leading-edge research to continually improve our understanding of threats to our system and our ability to prevent them. We examine the effectiveness of our operational controls and management system to determine if we have any unmitigated risks or areas where we are underperforming on safety and reliability.

We invest significantly in the fitness of our systems and in leak detection:

  • We monitor our systems 24/7, 365 days a year.
  • We continually inspect pipelines and facilities to ensure optimal safety and reliability performance.
  • We conduct visual right-of-way surveillance—both ground and air patrols—to watch for potential issues.
  • We verify our performance and protective measures.
  • We secure our systems against all identified threats.
  • We monitor our pipelines for possible leaks using multiple computerized systems, each with a different focus and each using different technology, resources and timing to provide overlapping and layered leak detection.

We actively research and develop new inspection, prevention and leak detection technologies to meet our needs and continually improve our ability to manage the hazards to our system.

Monitoring our Crude Oil Pipeline System

Controller monitoring: Our Supervisory Control and Data Acquisition (SCADA) system is designed to identify operational changes, such as pressure drops, that may indicate a leak. This SCADA system also monitors vapor concentrations, pump-seal failures, equipment vibration levels and sump levels.

Computational pipeline monitoring: We constantly monitor pressure, temperature and other key data from thousands of points along our systems to quickly identify and respond to unexpected changes. Computer-based systems use measurements and pipeline data to detect anomalies that could indicate possible leaks.

Scheduled line balance calculations: Many times a day, at regularly scheduled intervals, we calculate and confirm that the volumes of crude oil we receive into our pipeline systems precisely match the volumes we deliver.

Working inspecting a pipeline

Managing Hazards

How the integrity of a pipeline is managed depends on the threats the pipeline faces. Because every pipeline faces unique threats and stresses, Enbridge employs a wide range of risk assessment, inspection and surveillance techniques. Once threats and hazards have been identified, we select an optimal combination of controls and safety barriers to preserve integrity over the life cycle of the pipeline. As inspection technology, pipeline materials and construction practices improve with time, and new data on threats and pipeline condition are gathered, our methods of maintaining fitness for service evolve. For more information, please review our commitment to pipeline safety.

How We Prioritize and Respond to Threats


Key Priorities

  • External and internal corrosion.
  • Fatigue and stress corrosion cracking.
  • Geohazards (including slope movement, submarine currents and scouring at watercourse crossings).
  • Human error, including third -party mechanical damage to pipe, causing releases of hazardous material.
  • Achieve zero spills or leaks.
  • Maintain the fitness for service of our pipelines and facilities.
  • Focus on damage prevention, leak detection and corrosion prevention programs.
  • Ensure the quality of the assets we build.
  • Instill robust process safety management and high levels of operational discipline across the entire system.

How We Take Action

Design and Construction

Monitoring and Prevention

Leak Detection

  • Carefully select pipeline routes and facility locations.
  • Follow strict standards for engineering and design.
  • Extensively test new materials and technology before they are introduced.
  • Ensure designs meet or exceed all governmental codes and regulations to provide the safest and most reliable assets practicable.
  • Incorporate special design considerations for areas such as road, river and creek crossings and for high-consequence areas where the public may be affected.
  • Set rigorous standards for pipeline materials received from manufacturers and check to ensure they meet our standards and specifications.
  • Employ professional inspectors to oversee every facet of construction; use X-ray or ultrasound technology to inspect welds for potential defects.
  • Once pipelines are running, continuously monitor them for any signs of trouble.
  • Conduct in-line inspections to detect any signs of internal and external corrosion, cracking, strain, fatigue, dents and legacy manufacturing defects; repair any defects found.
  • Recognize conditions that have been known to cause failures and carefully analyze failures from our peers; work to minimize the risks.
  • Ensure adequate cathodic protection is provided to steel pipelines.
  • Minimize pressure cycling of liquids pipelines to prevent fatigue.
  • Conduct regular preventative maintenance.
  • Monitor land use changes and ground disturbance work around pipelines.
  • Inform the public, public works and excavating companies about the presence of pipelines and how to dig safely.
  • Locate pipelines for parties digging in the vicinity.
  • Investigate unauthorized activities on rights-of-way.
  • Devote resources—both people and automated systems—on a continuous, 24/7/365 basis to ensure control of pipelines and rapid response to abnormal situations.
  • Apply comprehensive, multi-layered leak detection system on liquids pipelines using several independent leak monitoring methods.
  • Monitor pipelines for possible leaks and damages using multiple, redundant methods.

For more details on our ongoing actions to maintain the fitness of our systems and detect leaks, please visit the following pages on
Crude Oil and Liquids Pipeline Systems Integrity; Crude Oil Pipeline Monitoring; Operations; and Natural Gas Systems Integrity.

Our Performance

Maintain Pipeline and Facility Integrity

In 2018, Enbridge invested more than $1.1 billion in programs that help us maintain the fitness of our systems and detect leaks across our operations. Over the past three years, our investment has totaled more than $3.7 billion.

Leak detection and performance chart
1The number of pipeline inspections includes direct assessments of pipeline integrity, in-line inspections and follow-up digs, hydrostatic pressure tests, inspections completed on bridges, inspections completed on slopes and water courses and other inspections completed, such as storage-well integrity inspections and valve inspections. Our CSR and Sustainability reports prior to the 2017 report have included primarily in-line inspections.
Leak detection and performance chart

Prevent Spills, Leaks and Releases

The integration of Spectra Energy in 2017 has approximately doubled the asset base of Enbridge, which has had a corresponding effect on the number of incidents that occurred across the expanded Enbridge system. For the purpose of our Sustainability Report, we include incidents that are significant and reportable to our Board of Directors:

  • Tier 1 events are commodity releases with greater consequences and/or higher release volumes.
  • Other Reportable incidents, termed Tier 2 events, are commodity releases with lesser consequences.

An injury or a fire as a result of a release often dictates classification of an event at a higher tier than the volume released would. Similarly, our management may decide to upgrade how we classify any event— including those that did not result in any spills, releases or harm, but that were potentially serious—to a higher tier if they deem doing so to be prudent. As such, the incidents that we include in this report have not all resulted in a spill or release.

Maintaining the Fitness of Enbridge’s Systems

Liquids/Liquids Systems Process Safety Incidents

Liquids/Liquids Systems Process Safety Incidents

Liquids Spills, Leaks and Releases

In 2018, we delivered more than 3.96 billion barrels of crude oil and natural gas liquids. We experience 14 process safety events, of which 11 involved the release of a liquid hydrocarbon. The other three involved other forms of uncontained and uncontrolled hazardous energy on a liquids pipeline (e.g. mechanical energy, heat). Of the 11 leaks and releases, two were deemed to be Tier 1 process safety events.

The total volume from the 2018 liquids spills, in all Enbridge business segments, was 411 barrels. Of this total liquids volume released, 206 barrels were on our Liquids Transmission Pipeline System and 205 barrels were in gas processing plants. All but 157 barrels were contained within plant/terminal boundaries or secondary containment. Based on volumes spilled and our gross delivery volumes, we achieved a safe delivery rate greater than 99.99999% in 2018.

Natural Gas Releases

Natural Gas Process Safety Incidents

Natural Gas Process Safety Incidents

In 2018, Enbridge transported and distributed more than 10.6 trillion cubic feet of natural gas through our natural gas pipelines and our natural gas distribution network. We experienced 26 reportable (Tier 1 and 2) process safety events involving the release of gas from process equipment on our natural gas systems. Of this total, we experienced 14 Tier 1 process safety events.

We experienced two significant incidents on our natural gas system in 2018 and two in 2019.

Andy Drake

“Ensuring the safety of our pipelines is a challenge we’re addressing from every perspective—technically, organizationally and culturally. We have set an expectation that we will not have any more failures. We’re developing a multi-faceted plan to meet that expectation with confidence. Safety comes first, without question. In the absence of certainty, fitness for service will not be assumed. Decisions about the safety of our assets are based on facts and data, driving toward quantitative statistical confidence in our assessments. And, assuring the diligence of our assessments through a deliberate quality control review process against our safety targets.”

Andy Drake,
Vice President of Asset Integrity, GTM

  • In October 2018, our T-South transmission pipeline ignited in a rural, forested area north of Prince George, British Columbia. There were no injuries associated with the rupture; however, approximately 5.2 hectares of forest were damaged in the fire. Immediately following the incident, the pipeline and an adjacent pipeline were shut down. The pipeline remained shut down until its fitness for service was confirmed and a return-to-service order was issued by the National Energy Board. The majority of the T-South system remains under a pressure restriction while Enbridge completes its comprehensive integrity program on the T-South system.
  • In December 2018, a release occurred on our East Tennessee pipeline near Pleasant Shade, TN. A nearby residence and two other buildings sustained limited damage from pipeline cover displaced in the release. Local residents were evacuated, and the pipeline was isolated and blown down without ignition. There were no injuries associated with the incident. Following repairs, gas supply to downstream customers was returned at a reduced pressure while Enbridge conducted its investigation and completes its comprehensive integrity program.
  • In January 2019, a rupture occurred on our Texas Eastern Pipeline in Noble County, OH. The rupture resulted in a fire that injured two people and damaged three nearby residences. We coordinated with and supported the Pipeline and Hazardous Materials Safety Administration (PHMSA) and the Public Utilities Commission of Ohio (PUCO) as the investigation progressed. Enbridge also conducted its own investigation. Following a completion of a comprehensive integrity assessment, all three pipelines were returned to service.
  • In August 2019, a rupture occurred on Line 15, part of our Texas Eastern transmission pipeline system, near Danville, KY, resulting in one fatality and several injuries. A number of homes were destroyed. The line was isolated, and the National Transportation Safety Board assumed control of the incident site and ensuing investigation, returning site control to Enbridge after eight days. PHMSA issued a Corrective Action Order which set out return to service and assessment requirements. The two adjacent pipelines to the impacted line were returned to service approximately one month later. At the time of the release of this report, Line 15 remains out of service.

In 2018, our natural gas utility delivered more than 1.8 trillion cubic feet of natural gas. A large number of small leaks are detected on our utilities network each year because of the significant number of natural gas delivery points. In the vast majority of cases, these below-ground or outside leaks are not hazardous due to the system’s low delivery pressure, small line capacity, and odourization, which serves as a warning sign.

The low-hazard nature of these small leaks means the majority fall below our reportable (Tier 2) process safety event criteria. Leaks due to third-party damage to pipeline assets make up a significant portion of these releases. To help prevent third-party damage, Enbridge has an extensive public education program for pipeline awareness and safe digging. Enbridge also supports and is a member of one-call/ locate services.

Detailed data related to the safety performance of all our businesses are located in the Performance Data.

Natural Gas Distribution Network





Damages per 1,000 third-party locate requests 2.17 1.92 1.96

*Reflects Enbridge Gas Distribution data only.

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