Uncharted Waters: Mapping Canada’s Path to Prevent Pollution from Shipwrecks

In this article, you will learn:

• Why some shipwrecks pose a high risk of pollution
• How potentially polluting wrecks are identified
• Where these wrecks are located
• What is being done about shipwrecks in Canadian waters

Given the estimated 3 million sunken and abandoned vessels globally,¹ identifying where they are, whether they contain oil, and how to prevent future oil spills is part of worldwide efforts to reduce harm to the ocean environment and those who depend on it.  

To understand this threat in Canadian waters, Canadian Coast Guard staff have evaluated wrecks for their pollution threat. While this initial effort identified the probable location and condition of wrecks, a detailed scan and intrusive survey of each vessel would be required to know whether the vessel contains oil or other hazardous substances and how to deal with it.

Are all shipwrecks a threat?

Initially, ships were powered by wind or people. Oil became the ship fuel of choice in the early 20th century.² When vessels carrying oil as fuel and as cargo sank, that oil could remain trapped, threatening future oil spills.

In addition to oils trapped in holds or tanks aboard a sunken vessel, wrecks can contain hazards like greases, toxic paints, and plastics.³ In some cases cargo like chemicals or unexploded munitions⁴ remain onboard. Not all shipwrecks are potentially polluting, but determining the location and condition of the vessels that do pose a threat is an important step in understanding the issue.

Why deal with wrecks now?

For much of seafaring history when a vessel sank, it was gone—unless it posed an “immediate pollution threat” or “impeded navigation.”⁵ While salvage operations and efforts to recover oil or cargo may have been attempted, these actions were not mandated if the wreck was not leaking.

Before 2019 and the introduction of the Wrecked, Abandoned or Hazardous Vessels Act, it was not illegal to abandon a vessel in Canadian waters. Therefore, if a vessel was not actively leaking oil, there was no legal requirement for the owner to address the wreck, even if the presence of oil or hazardous cargo on board posed a future environmental threat.

Canadian waters have their share of long forgotten and potentially polluting wrecks. The MV Schiedyk and USAT General Zalinski in British Columbia, the SS Arrow in Nova Scotia, and the Manolis L in Newfoundland and Labrador have each made headlines. When slicks mysteriously appeared on the surface, the Canadian Coast Guard first had to mop up the actively leaking oil and then remove the remaining oil from the wreck. These emergency actions were costly and difficult. Furthermore, the time needed to trace the spill to its source in some of these cases—initially thought to be spills from passing vessels—prolonged the clean-up effort. 

Dealing with polluting shipwrecks is both difficult and costly, requiring specialized skills and technology along with large numbers of people. Research in this area has established that proactive operations cost significantly less than responding to wrecks on an emergency basis.⁶ While a proactive approach might seem like the obvious answer, to date, Canada has only dealt with wrecks once they begin to leak. 

Addressing any wreck, whether actively polluting or not, is a complex undertaking. The risks in either a proactive or emergency response include those to human life and the environment. As wrecks can be precariously placed on the seabed and in an advanced state of decay, one risk is the recovery work catastrophically damages a wreck, leading to a sudden release of oil rather than the intended recovery of oil.

When planning a response to a wreck, the amount of oil on board is estimated based on often sparse information. Paul Barrett, Regional Director of Operations, Western Region for the Canadian Coast Guard and author of a dissertation that provided a risk assessment framework for potentially polluting wrecks in Canadian waters⁷, noted that some proactive operations undertaken in other countries recovered little to no oil, incurring considerable cost for no tangible benefit. Any plan to respond proactively to a wreck needs to weigh the anticipated environmental benefit against expected financial costs—both of which could change once the operation is underway.

How are potentially polluting wrecks identified? 

An international survey conducted in 2005 by a group of researchers began to quantify the issue of potentially polluting wrecks. They found 8,000 sunken vessels containing an estimated 2 to 20 million tonnes of hydrocarbons.⁸ In the wake of these findings, many countries including the USA, the EU, Sweden, Norway, the UK, and a multinational group in the South Pacific, conducted their own assessments to understand the risk of spills from wrecks in their regions. In the US, the National Oceanic and Atmospheric Administration (NOAA) completed a risk assessment in 2013 of the estimated 20,000 sunken wrecks in US waters. The resulting RULET database was used to assess 87 wrecks and identify 36 that posed the greatest threat of pollution.

Canada likewise has begun to work to better understand what lies beneath our waters starting with Paul Barrett’s research. Barrett developed a methodology to assess the risk of wrecks in Canada. This methodology was applied to identify, locate, and rank wrecks to the extent possible using public records. Within the Canadian Coast Guard, the results of this initial wreck mapping effort have informed a potentially polluting wrecks strategy. 

The location and risk ranking for each wreck are shown in the maps in figures 1, 2, and 3. The locations and risk rating are only an initial estimate. In many cases, the exact location of the wreck and the amount of oil or other hazardous materials on board have yet to be verified.  

Where did all these wrecks come from?

Eighty years ago, the Second World War “saw the greatest-ever loss of shipping: more than three quarters of the oil-containing wrecks around the globe date from the six years of this war.”⁹ Many vessels sank in Canadian waters during the wartime period and as these vessels have been sitting on the bottom of the ocean, their hulls have been slowly rusting. The rate of corrosion varies depending on environmental conditions; however, experts estimate we are approaching “peak leak”—a period when many of these vessels’ hulls will give way to either a slow, gradual release of oil from its tanks or a catastrophe rupture spilling all the oil at once.¹⁰ As has already been experienced in Canadian waters, oil leaking from wrecks is a significant hazard and is expected to become more common.  

Vessels from the after the Second World War also lay in the deep. Some modern vessels lost such as the Queen of the North ferry have been surveyed, and the risk of moving them presents a greater potential for environmental damage than leaving them as they are.¹¹ Some vessels believed to be in a certain location were not, after a detailed survey was done. Other vessels still need to be located and surveyed.  

What is being done to mitigate the risk of potentially polluting wrecks?

While accidents at sea leading to shipwrecks still occur, improved weather forecasting and new technologies such as radar, Automatic Identification Systems, and Global Positioning Systems have reduced the frequency of shipwrecks. Only 38 ships were lost globally in 2022.¹²  

Paul Barrett noted that potentially polluting wrecks are not only a Canadian issue; countries around the world are grappling with the magnitude of the clean-up required. Internationally, the Nairobi International Convention on the Removal of Wrecks (2007) has provided countries with a uniform legal framework to address shipwrecks that “have the potential to affect adversely the safety of lives, goods and property at sea, as well as the marine environment.”¹³  

The Canadian Coast Guard has undertaken two trips to conduct visual surveys of known wrecks in Canada’s Pacific region. One trip took place off Vancouver Island in 2022¹⁴ as a collaboration between the Royal Canadian Navy and the Canadian Coast Guard, using sonar to scan the seabed and divers to investigate wrecks. Further exploration may occur in the future when opportunities arise.

Canada has also improved its legislation and frameworks to have ship operators take responsibility in the event of a future accident. Canada applies the polluter pays principle, meaning the costs associated with cleaning up a spill fall to those responsible and not the public. The Ship-source Oil Pollution Fund provides compensation when the polluter cannot, including clean-up costs in Canadian waters. Unfortunately, the Ship-source Oil Pollution Fund cannot be used to address wrecks sunk prior to 2019, when the Wrecked, Abandoned or Hazardous Vessels Act came into effect.  

What is next for wrecks in Canadian waters?

While no proactive clean-up of wrecks has yet occurred in Canada, the database of wrecks in Canadian waters ranked by estimated risk, and the resulting potentially polluting wrecks strategy are a starting point. Canada has the longest coastline of any country in the world, with over 7.1 million square kilometres of ocean territory.¹⁵

Locating and addressing all potentially polluting wrecks will be no small undertaking and presents a significant financial burden. However, waiting until an emergency response is required increases the cost of clean-up and inflicts damage on the environment.

By taking action to address these “slicking time bombs” proactively and appropriately, Canada has an opportunity to reduce the costs associated with emergency spill response, prevent environmental damage, and protect its sensitive marine ecosystems. 

References

1. Marine pollution from sunken vessels. (2023). International Union for Conservation of Nature. ↩︎
2. History and Transition of Marine Fuel. (2021). MOL Mitsui O.S.K. Lines Service Site. ↩︎
3. Whose Boat Is It Anyway? The Pitfalls And Jurisdictional Complications Of The Canadian Problem Boat Regime. (2022). The Canadian Bar Association. ↩︎
4. Marine pollution from sunken vessels. (2023). International Union for Conservation of Nature. ↩︎
5. Potentially Polluting Wrecks in U.S. Waters. (2023). National Oceanic & Atmospheric Administration National Marine Sanctuaries. ↩︎
6. Barrett, P. 2021. “Development and application of a risk assessment framework for potentially polluting wrecks in Canadian waters.” Dissertation project proposal submitted to MLA College in partial fulfilment of the requirements for the degree of B.Sc. (Hons) Sustainable Maritime Operations. ↩︎
7. Barrett, P. 2021. “Development and application of a risk assessment framework for potentially polluting wrecks in Canadian waters.” Dissertation project proposal submitted to MLA College in partial fulfilment of the requirements for the degree of B.Sc. (Hons) Sustainable Maritime Operations. ↩︎
8. Barrett, P. 2021. “Development and application of a risk assessment framework for potentially polluting wrecks in Canadian waters.” Dissertation project proposal submitted to MLA College in partial fulfilment of the requirements for the degree of B.Sc. (Hons) Sustainable Maritime Operations. ↩︎
9. Why wartime wrecks are slicking time bombs. (2010). New Scientist. ↩︎
10. Why wartime wrecks are slicking time bombs. (2010). New Scientist. ↩︎
11. Queen of the North to stay sunk. (2007). The Globe and Mail. ↩︎
12. Facts + Statistics: Marine Accidents. (2023). Insurance Information Institute. ↩︎
13. Nairobi International Convention on the Removal of Wrecks. (2019). International Maritime Organization. ↩︎
14. HMCS Yellowknife supports Canadian Coast Guard in wreck survey. (2022). Lookout Production. ↩︎
15. Canada’s oceans estate: A description of Canada’s maritime Zones. (2007). DFO/2007-1199, ISBN 978-0-662-45436-6 ↩︎