10.3 Trends in spills of hazardous materials

Last Updated: 
May 27, 2015

This indicator tracks the number of hazardous materials spills in each ecozone of the NWT. Hazardous materials includes any substance that may include contaminants, such as hydrocarbons or metals. Spills are reported within 24 hours, investigated and information on each event is compiled.

Fuel spill
Fuel spill.

Information for this indicator is obtained from the Hazardous Materials Spill Database with analysis from annual Spills in the Northwest Territories reports.

NWT focus

Northern ecosystems are fragile. Petroleum degrades very slowly in cold climates and increases risks of exposure to wildlife and plants. Different types of activities are linked to different types of spills. Each spill has its own materials and levels of risk to the environment.

“The risk of petroleum spills is associated primarily with the transport and storage of fuels for community and industrial needs. To service the needs of remote coastal and river communities, barges and other large marine vessels provide bulk fuel and supplies. Communities located along highway systems are provided with petroleum by tanker truck. Once delivered to communities, mine sites and other locations, the large volumes of petroleum must then be stored for eventual use in vehicles, furnaces and electrical generators."

“Depending upon the size and number of years a mine operates many thousands of tonnes of waste rock and tailings may be produced. Unless mining companies carefully control the discharge of water from their tailings ponds, metal and sediments from these ponds can affect the aquatic environment downstream for many years. If a tailings pond is allowed to become dry, tailings dust can also be distributed to surrounding land and water by the wind. There are also significant potential impacts from mining operations as a result of the release of metal-bearing wastes. The potential for contamination comes from the weathering of waste rock and rock exposed during the mining activities as well as accidental spillage of mill tailings. Exposure of iron pyrite and other sulphur bearing minerals to atmospheric oxygen in the presence of moisture leads to acid weathering reactions. These reactions could lead to acid mine drainage and the continual dissolving of metals from waste rock and tailings. This leachate is a potential long-term source of metals to the environment where they can be taken up by plants and animals.”

"The main emissions associated with oil and gas activities are the discharge of drilling wastes, atmospheric emissions and accidental spills of petroleum. It is common industry practice to dispose of waste drilling fluids on land into sumps adjoining the oil rig. These wastes contain various pollutants ranging from metal salts to petroleum hydrocarbons.”1

Current view: status and trend

In total amounts spilled in the NWT annually, the highest (93%) is wastewater, including sewage, salty ground water brought to the surface by oil and gas extraction, and mine tailings.

The remaining spills are fuel oil and various chemicals, such as antifreeze and glycol-based products for vehicles, lube oil and other hydrocarbons.


Volume of hazardous material spills in the NWT by product - five year average
Volume of hazardous material spills in the NWT by product - five year average.


Number of spills in the NWT by product - 2014
Number of spills in the NWT by product - 2014.

Reported spills in 2014 by sector are 29 % from mining 29%; 25% from federal, territorial and municipal government activities; 11 % from oil and gas exploratin and development; 6% from private activities; 3% from transportation; and, 26% from unknown or other parties. Most of the reported spills are of fuel oil in communities, 39% in 2014, and are of very small amounts (less than 100 litres). These spills have been decreasing in frequency since the release of the ENR Homeowners Guide to Oil Tanks. Small spills usually involve blown hydraulic lines or leaks from heavy equipment, haul trucks or smaller industrial vehicles, such as pick-ups leaking engine and transmission fluids. The majority of spills in the NWT are considered minor in nature and are less than 100L.

Number of spills in the NWT, by size
Number of spills in the NWT, by size.

Looking forward

Changes in the number of spills of hazardous materials occurring each year correspond to changes in the NWT’s resource-based economy. Trends in spills larger than 100 litres may rapidly decrease with reduced activities in the mining,  oil and gas sectors. However, efforts to reduce the number of potential spills with more efficient prevention and education programs continue. Developing clean-up technologies in extremely cold and remote environments remains a challenge.

“At present, technology for cleaning up spilled petroleum is not adequate to remove oil from ice-covered waters and there is the potential for a major environmental disaster within Arctic fresh and marine waters if a barge or tanker was to spill its petroleum cargo. Although highway tanker trucks carry a significantly smaller volume of fuel than do barges or tanker ships, the increasing volume of truck traffic along northern highways and ice roads continue to threaten terrestrial and aquatic environments located adjacent to these roads.” 1

Looking around

The Northwest Territories/Nunavut Spills Working Group was established to foster a cooperative and one-window approach to reducing spills in the North. This group ensures a comprehensive regulatory coverage of all spills in the NWT between federal and territorial governments. 

Internationally, ENR is also a member of the Arctic Council's Emergency Prevention Preparedness and Response (EPPR) working group. This working group focuses on risk analysis and guidance documentation.

For more information

Contact us

Found an error or have a question? Contact the team at NWTSOER@gov.nt.ca.


Ref.1. Environmental Protection. Government of the Northwest Territories. 1998. Pressures on the Arctic ecosystem from human activities. GNWT-ENR.

Updated: May 27, 2015