Pipeline safety incident glossary

Here's a look at what is considered a pipeline incident by the National Energy Board, the federal regulator of cross-border pipelines. We've also included terms you may encounter in the various pulldown menus.

Incident: The NEB has very specific criteria for what constitutes a pipeline incident and thus is considered reportable to the regulator. It includes:

  • a death or serious injury of a person.
  • a significant adverse effect on the environment.
  • an unintended fire or explosion, and unintended/uncontained release of low vapour pressure hydrocarbons in excess of 1.5 cubic metres (1,500 litres).
  • any unintended/uncontrolled release of gas or high vapour pressure hydrocarbon.
  • operation of a pipeline beyond its design limits.

Types of events

The following are types of events used by the NEB to classify incidents involving pipelines.

Environmental release: A term the NEB no longer uses when classifying types of pipeline safety-related events. The board put a “do not use” label on it to remind staff that this category should not be selected.

Equipment failure: Another term the NEB no longer uses in its database collection. This was used when a piece of equipment malfunctioned, often resulting in a leak. Fatality: Pipeline companies must provide information on any death involving employees, contractors or members of the public related to the construction, operation or maintenance of pipelines.

Fire/explosion: Any time a fire or explosion is unintended it must be reported to the NEB.

Other event: This category for reportable incidents can include any incidents such as a spill of a non-product like produced water or a pipeline operated beyond its design, such as pressures that are too high.

Pipeline rupture: This term is used whenever a pipeline suffers a “loss of containment” and is unable to operate.

Release of product: This refers to anytime a pipeline company's product is unintentionally released. That can be anything from exhaust to a spill. However, not all releases must be reported. It depends on whether it's a high or low vapour pressure product. See definitions above.

Serious injury: Pipeline companies must only report an injury if it involves a serious injury, defined as suffering a major bone fracture, a body part amputation, loss of sight in one eye or both, internal haemorrhage, third-degree burns, unconsciousness, loss of a body part or loss of a function of a body part.

Types of substances

The NEB requires pipeline companies to report when their product is released, but the threshold varies depending on the type of substance. There are two key types for their products -- high and low vapour -- plus several others.

Low vapour pressure (LVP) product: This includes products such as oil, synthetic oil and heavy oil that flow through pipelines in liquid form.

High vapour pressure (HVP) product: This includes more volatile products such as propane, butane and other natural gas liquids that can quickly convert to gaseous form at atmospheric pressure.

Commodities: Any pipeline carrying products other than oil or gas are called commodity lines. This excludes municipal sewer and water lines. These pipelines are regulated on a case-by-case basis, not by the Onshore Pipeline Regulations others must follow. Examples of commodities running through Canadian pipelines include carbon dioxide and sulphur. Eleven incidents are noted in the database.

Natural gas: Any unintended release of gas must be reported to the NEB.

Miscellaneous: This includes a number of substances, such as glycol, amine, hydrogen sulphide and grey water/sewage. Companies may have reported these due to requirements they report anything that could have a significant adverse effect on the environment.


This refers to the material that was released. The category features a wide range of substances. Here are definitions for the key ones.

Bitumen: A mixture that is too thick to flow through pipelines unless heated or diluted. It's the heaviest, thickest form of petroleum, and can either be found in oils sands deposits or the residue of distilled crude oil.

Chlorodifluoromethane: A colourless gas that is nonflammable. Also known as freon and used as a refrigerant or in the production of energy.

Crude oil: A mixture of liquid hydrocarbons extracted from rock to use as fuel or in chemical processing. It's categorized as sweet or sour depending on the amount of sulphur, which is removed during refining.

Sour crude oil: Crude oil with a higher sulphur content.

Sweet crude oil: Crude oil with lower sulphur content.

Synthetic crude oil: A partially processed hydrocarbon blend created to make it transportable. It can be made from extra heavy oil, shale oil and oil sands.

Diluent: A lighter hydrocarbon added to heavy crude oil or bitumen to help it move through the pipelines.

Hydrocarbon: A chemical compound of carbon and hydrogen. Hydrocarbons are the main parts of petroleum and natural gas.

Hydrogen sulphide: A colourless gas known for its rotten egg smell, it is extremely flammable and toxic.

Liquefied natural gas: This is natural gas in its liquid form, which is achieved by cooling it. The process can reduce the volume of gas by 600 times, making for more efficient transport.

Natural gas: A colourless, highly flammable gaseous hydrocarbon. It has a high percentage of methane and ethane.

Natural gas liquids: This refers to a group of hydrocarbons found in natural gas that are separated out as the following liquids: ethane, propane, butane and pentane.

Produced water: The salty water trapped in reservoir rock that is emitted during oil or gas production. It can contain minor amounts of chemicals from the process. Sour natural gas: This gas includes hydrogen sulphide, a highly toxic chemical that smells like rotten eggs and can be fatal if a certain amount is inhaled.

Sweet natural gas: This gas consists mostly of methane. It is colourless and odourless.

Other terms

Right-of-way (ROW): This is a strip of land on private property where the company has legal right to access in order to build, operate and maintain the pipeline. Landowners can use the property, but with restrictions. The area remains clear and markers on the land alert the public to the pipelines.

Source: Canadian Standards Association, National Energy Board Onshore Pipeline Regulations, National Energy Board, Environment Canada Glossary