The Enbridge Pipeline System is an

oil An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) and lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturate ...

pipeline system which transports crude oil and

dilbit Dilbit (diluted bitumen) is a bitumen diluted with one or more lighter petroleum products, typically natural-gas condensates such as naphtha. Diluting bitumen makes it much easier to transport, for example in pipelines. Per the Alberta Oil Sands B ...

from Canada to the United States. The system exceeds in length including multiple paths. More than of the system is in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

while the rest is in

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

and serves the

Athabasca oil sands The Athabasca oil sands, also known as the Athabasca tar sands, are large deposits of oil sands rich in bitumen, a heavy and viscous form of petroleum, in northeastern Alberta, Canada. These reserves are one of the largest sources of unconventi ...

production facilities. Main parts of the system are Canadian Mainline and Lakehead System (U.S. Mainline). On average, it delivers of

crude oil Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring u ...

and other products to the major

oil refineries An oil refinery or petroleum refinery is an industrial process plant where petroleum (crude oil) is transformed and refined into products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, liquefied pet ...

in the American

Midwest The Midwestern United States (also referred to as the Midwest, the Heartland or the American Midwest) is one of the four census regions defined by the United States Census Bureau. It occupies the northern central part of the United States. It ...

and the Canadian province of

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

. The Canadian portion is owned by

Enbridge Enbridge Inc. is a multinational pipeline transport, pipeline and energy company headquartered in Calgary, Alberta, Canada. Enbridge owns and operates pipelines throughout Canada and the United States, transporting crude oil, natural gas, and n ...

, while the U.S. portion is partly owned by that company through Enbridge Energy Partners, LP, formerly known as Lakehead Pipe Line Partners and Lakehead Pipe Line Company.

Background

The first portion of the pipeline was built over the course of 150 days in 1950 by a 1,500-man labor force. It crossed approximately from Redwater, Alberta, through

Saskatchewan Saskatchewan is a Provinces and territories of Canada, province in Western Canada. It is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and to the south by the ...

Manitoba Manitoba is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population ...

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

, and

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

, to the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...

seaport A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Hamburg, Manc ...

Superior, Wisconsin Superior (; ) is a city in Douglas County, Wisconsin, United States, and its county seat. The population was 26,751 at the 2020 United States census, 2020 census. Located at the western end of Lake Superior in northwestern Wisconsin, the city l ...

. At the same time, four

oil tanker An oil tanker, also known as a petroleum tanker, is a ship designed for the bulk cargo, bulk transport of petroleum, oil or its products. There are two basic types of oil tankers: crude tankers and product tankers. Crude tankers move large quant ...

s were constructed to carry the crude from Superior to

Sarnia, Ontario Sarnia is a city in Lambton County, Ontario, Canada. It had a Canada 2021 Census, 2021 population of 72,047, and is the largest city on Lake Huron. Sarnia is located on the eastern bank of the junction between the Upper and Lower Great Lakes, ...

. Oil first entered the pipe on August 25, 1950, and the first tanker, ''Imperial Leduc'', was launched on November 4. Other tankers that followed were, ''Imperial Redwater'', ''Imperial Woodbend'', and ''B.A. Peerless''. Because the lakes froze in the winter, preventing tanker traffic, the decision was soon made to expand the pipeline all the way to Sarnia. In May 1953, contracts were awarded and construction began. At , it became the world's longest pipeline. A major upgrade was undertaken in the 1990s to replace old pipe and expand the system.

Mainline system

Today, there are two routes that oil can take between Superior and Sarnia. A northern route passes through the upper and

lower Lower may refer to: * ''Lower'' (album), 2025 album by Benjamin Booker *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is sit ...

peninsulas of

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

before crossing into

, while the southern route circles south of

Lake Michigan Lake Michigan ( ) is one of the five Great Lakes of North America. It is the second-largest of the Great Lakes by volume () and depth () after Lake Superior and the third-largest by surface area (), after Lake Superior and Lake Huron. To the ...

through

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

and

Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...

before reaching Michigan. There are 59 pumping stations in the pipeline system, and the actual pipes range in diameter from . One major junction point is in Clearbrook, Minnesota where the pipeline connects to the Minnesota Pipeline, which carries crude to the Pine Bend Refinery in

Rosemount, Minnesota Rosemount is a city in Dakota County, Minnesota, United States, on the southern edge of the Twin Cities Metropolitan Area. The population was 25,650 at the 2020 census. History Rosemount was established as a township in 1858 and incorporated ...

. The North Dakota Pipeline Company system of pipeline also has a connection in Clearbrook, linking the Mandan Refinery in

Mandan, North Dakota Mandan is a city on the eastern border of Morton County, North Dakota, Morton County and the List of cities in North Dakota, eighth-most populous city in North Dakota. Founded in 1879 on the west side of the upper Missouri River, it was designat ...

. The Murphy Oil refinery in

, is directly linked to the pipeline. Another point in

Lockport, Illinois Lockport is a city in Will County, Illinois, United States, located 30 miles southwest of Chicago. Per the 2020 United States census, 2020 census, the population was 26,094. The city was incorporated in 1853. It is situated along the Illinois a ...

connects two pipelines to

Patoka, Illinois Patoka is a village (United States)#Illinois, village in Marion County, Illinois, Marion County, Illinois, United States. The population was 525 at the 2020 census. History The village was named after a local Native American chieftain. Geograph ...

, plus a longer link to

Cushing, Oklahoma Cushing (, , ''meaning: "Soft-seat town"'') is a city in Payne County, Oklahoma, United States. The population was 7,826 at the time of the 2010 census, a decline of 6.5% since 8,371 in 2000. Cushing was established after the Land Run of 1891 b ...

. A relatively short link from

Stockbridge, Michigan Stockbridge is a village in Ingham County in the U.S. state of Michigan. It is located within Stockbridge Township about southeast from downtown Lansing. The population was 1,244 at the 2020 census. Geography According to the United States ...

connects to two refineries in the

Toledo, Ohio Toledo ( ) is a city in Lucas County, Ohio, United States, and its county seat. It is located at the western end of Lake Erie along the Maumee River. Toledo is the List of cities in Ohio, fourth-most populous city in Ohio and List of United Sta ...

area. The Mainline system, conventionally divided into the US and Canadian mainlines, consists of 1900 miles of pipeline that run from central

Alberta Alberta is a Provinces and territories of Canada, province in Canada. It is a part of Western Canada and is one of the three Canadian Prairies, prairie provinces. Alberta is bordered by British Columbia to its west, Saskatchewan to its east, t ...

to southern

via the northern US. The system can carry up to 2.5 million barrels of oil per day. Lines 1 through 4 connect Edmonton to

. From there, Line 5 runs through the

Upper Peninsula The Upper Peninsula of Michigan—also known as Upper Michigan or colloquially the U.P. or Yoop—is the northern and more elevated of the two major landmasses that make up the U.S. state of Michigan; it is separated from the Lower Peninsula b ...

of Michigan and across the

straits of Mackinac The Straits of Mackinac ( ; ) are the short waterways between the U.S. state of Michigan's Upper and Lower Peninsulas, traversed by the Mackinac Bridge. The main strait is wide with a maximum depth of , and connects the Great Lakes of Lake M ...

to cross back into Canada at the

St. Clair River The St. Clair River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed November 7, 2011 river in central North America which flows from Lake Huron into Lake St. Clair, forming part ...

. Line 6 runs south through Wisconsin and Illinois to the terminal in

Griffith, Indiana Griffith is a town in North and St. John townships in Lake County, Indiana, United States. It is a part of the Chicago metropolitan area. The population was 16,420 in 2020. The town's population is currently declining at a rate of 0.69% annuall ...

, which serves BP Whiting and other Chicago-area clients, and then continues on through northwest Indiana and southern Michigan to rejoin Line 5 at

. The Mainline system comprises Lines 1, 2, 3, 4, 5, 6, 7, 10, 11, 14, 61, 62, 64, and 67. Pipelines that connect to the system, but are not part of it, include Line 9 (Montreal to Sarnia), Line 17 ( Stockbridge to Toledo), and Line 55 ( Flanagan to Cushing).

Expansion

As of 2013 there were expansion plans for the pipeline system which would, if permitted and fully built, provide the capacity to transport an amount of

from the

into the United States and the Gulf Coast equal to that of the

Keystone Pipeline The Keystone Pipeline System is an Pipeline transport, oil pipeline system in Canada and the United States, commissioned in 2010, formerly owned by TC Energy. It is now owned by South Bow, following TC Energy's spin off of its liquids business i ...

Accidents and incidents

Largest inland oil spill In U.S. history

In 1991, Enbridge's

Line 3 pipeline The Line 3 pipeline is an oil pipeline owned by the Canadian multinational pipeline and energy company, Enbridge. Operating since 1968, it runs mainly from Hardisty, Alberta, Canada all the way to Superior, Wisconsin, United States. Concerns ...

spilled 1.7 million gallons of oil in

Grand Rapids, Minnesota Grand Rapids is a city in, and the county seat of, Itasca County, Minnesota, United States. The population was 11,126 at the 2020 census. The city is named for the long rapids in the Mississippi River which was the uppermost limit of practi ...

and the Prairie River, a tributary of the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

. It was the largest inland spill of oil in U.S. history. Deliberations over construction of a new Line 3 pipeline have drawn resistance from

climate justice Climate justice is a type of environmental justice that focuses on the unequal impacts of climate change on marginalized or otherwise vulnerable populations. Climate justice seeks to achieve an equitable distribution of both the burdens of clima ...

organizers and Native communities in Minnesota.

Cohasset, MN oil spill

On July 4, 2002, 252,000 gallons of crude oil spilled into a marsh near

Cohasset, Minnesota Cohasset ( ) is a city in Itasca County, Minnesota, United States. The population was 2,689 at the 2020 census. U.S. Highway 2 serves as a main route in Cohasset. History A post office called Cohasset has been in operation since 1892. The c ...

due to a rupture of Line 4 running from Edmonton, Alberta, Canada, and

.National Transportation Safety Board. (2002).
Rupture of Enbridge Pipeline and Release of Crude Oil near Cohasset, Minnesota
''. Pipeline Accident Report NTSB/PAR-04/01. Washington, DC: Author. Emergency responders enacted a

controlled burn A controlled burn or prescribed burn (Rx burn) is the practice of intentionally setting a fire to change the assemblage of vegetation and decaying material in a landscape. The purpose could be for forest management, ecological restoration, ...

at 4:45pm the next day to prevent the oil from penetrating into any waterways. The cost of remediating the accident was reported around $5.6 million.

Clearbrook Junction, MN fire

On November 28, 2007, a large fire erupted during pipeline repair work at the Clearbrook Junction. This fire, described by a spokesperson for the Minnesota Department of Public Safety as a "big fire, not an explosion", killed two workers and caused a $4 per barrel spike in oil prices the following day. The pipeline carries crude from

to the

Chicago Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...

area.

Kalamazoo River oil spill

On July 26, 2010, 840,000 gallons of

crude oil leaked from the pipeline in

Calhoun County, Michigan Calhoun County is a county in the U.S. state of Michigan. As of the 2020 Census, the population was 134,310. The county seat is Marshall. The county was established on October 19, 1829, and named after John C. Calhoun, who was at the time ...

, spilling into Talmadge Creek that flows into the

Kalamazoo River The Kalamazoo River is a river in the U.S. state of Michigan. The river is long from the junction of its North and South branches to its mouth at Lake Michigan, with a total length extending to when one includes the South Branch.U.S. Geologic ...

. Despite alarms at Edmonton headquarters it took eighteen hours and a report from a Michigan utilities employee before the pipeline company acted to halt the flow finally. Enbridge reached a settlement with the U.S. Department of Justice and Environmental Protection Agency for a total of $177 million in response to the spill, along with an additional spill in Romeoville, Illinois later that year. This settlement included $110 million in spill prevention, $62 million in Clean Water Act violations, and $5.4 million in cleanup costs. In addition, the company was fined $3.7 million by the

United States Department of Transportation The United States Department of Transportation (USDOT or DOT) is one of the executive departments of the U.S. federal government. It is headed by the secretary of transportation, who reports directly to the president of the United States a ...

due to 24 violations in pipeline safety regulation. Under its agreement with the federal government, Enbridge was required to hold community open houses along pipeline routes. By 2014, the cost of cleanup to the company totaled to $1.21 billion.

Mackinac Straits Tugboat anchor incident

In 2018, a tugboat dropped its anchor on the pipeline near the

Straits of Mackinac The Straits of Mackinac ( ; ) are the short waterways between the U.S. state of Michigan's Upper and Lower Peninsulas, traversed by the Mackinac Bridge. The main strait is wide with a maximum depth of , and connects the Great Lakes of Lake M ...

in Michigan, denting the pipe and causing of

mineral oil Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral source, particularly a distillate of petroleum, as distinct from usually edible vegetable oils. The name 'mineral oil' by itself is imprecise, ...

to leak from two electric cables.

Fort Atkinson, WI diluent leak

On April 26, 2019, a faulty elbow joint caused a leak in Enbridge's Line 13. Between 29 and 33 barrels of diluent were released into the soil near Blackhawk Island, Wisconsin, outside Fort Atkinson. Enbridge did not report the spill to the Wisconsin Department of Natural Resources until July 31, 2020, over a year later.

Cambridge, WI oil spill

On November 11, 2024, Approximately 70,000 gallons of crude oil were discovered to have spilled from a pipeline near Cambridge, WI. It was detected during a routine check of the Cambridge station when "an Enbridge Technician noticed what appeared to be product staining an area of gravel" near a discharge valve, according to a report on the incident by the Federal Hazardous Materials Safety Administration. The spill is reported to have contaminated soil and groundwater, but effects are currently unknown, with a nearby creek seemingly unaffected.

Bibliography

* *

References

External links

Enbridge

Enbridge Asset Map (current)
{{Canadian pipelines * Oil pipelines in Alberta Oil pipelines in Indiana Transport in Manitoba Pipelines in Michigan Oil pipelines in Minnesota Oil pipelines in North Dakota Pipelines in Ontario Pipelines in Saskatchewan Oil pipelines in Wisconsin Oil pipelines in Canada Crude oil pipelines in the United States Energy infrastructure in Illinois Enbridge Oil spills in Alberta Environmental issues in Alberta Athabasca oil sands