Legal Header

Updated June 2021


Incident Ratings

We rate the effect an incident has on the public, land, environment, wildlife, and livestock as being high, medium, or low:

  • High consequence: Incidents that could have significant effect on the public, wildlife, or livestock or that involve the release of a substance that affects flowing water.
  • Medium consequence: Incidents that could have a moderate effect on the public, wildlife, or livestock or affect muskeg or stagnant water.
  • Low consequence: Incidents that involve little to no substance release; little to no effect on the public; no effect on wildlife; no effect on livestock; and do not involve the release of a substance that affects a large area or water body.

All incidents give us an opportunity to better understand what causes incidents so that we can work toward improving pipeline performance and preventing incidents.

Types of Incidents

The AER classifies each pipeline incident into one of the following five types:

  • leak
  • rupture
  • hit
  • gasket, seal, packing gland, or threaded fitting (GSPT) release
  • installation leak

Not all incidents mean that there has been a failure. A failure means the pipeline has failed to contain the substance being transported (i.e., leaks and ruptures). Incidents include events where a pipeline may have been contacted (hit), but a release of substance has not occurred.

Leaks and Ruptures

Pipeline leaks and ruptures, collectively referred to as pipeline failures, typically result in a release of a substance. Pipeline ruptures immediately impair pipeline operations, whereas pipeline leaks may not. However, pipeline leaks typically cause the largest spills simply because they can go undetected for a longer period of time. Leaks are the most common type of pipeline incidents, and all of the incidents rated as high or medium consequence are either a leak or a rupture. As a result, leaks and ruptures are reviewed thoroughly to help identify causes and trends, which in turn helps the AER with industry education and prevention.


A hit is when a pipeline is contacted and damaged during a ground disturbance but does not release a substance. Any person or company in Alberta that damages a pipeline while carrying out a ground-disturbance activity must report the incident to the AER so that we can inspect the site to see if it is safe, that the pipeline has not been compromised, and that corrective action has been taken to prevent future occurrences.

All companies must be registered with Alberta One-Call, which helps excavators identify underground infrastructure in their dig area. Most pipeline hits are caused by the operators themselves when excavating, digging, trenching, or conducting other forms of ground disturbance near an existing pipeline. Under the Pipeline Rules, permission from the pipeline owner is required when working near an existing pipeline to minimize the chances of such an event.

GSPT Releases

GSPT releases are always aboveground releases and rated as low consequence because very low volumes are released. GSPT releases usually occur at a gasket, seal, packing gland, or threaded fitting and can easily be addressed by replacing the problematic gasket or seal or making routine mechanical adjustments, such as tightening bolts. Although these are typically maintenance issues, they are reportable incidents as per the Pipeline Act.

Installation Leaks

Installation leaks are leaks from equipment installed at an auxiliary site associated with a pipeline, such as a compressor, pumping station, tank farm, or meter station that is listed as an installation on the pipeline licence. These incidents are not very common and are typically of low consequence.