With a number of pipeline projects underway across Canada, a Greenpeace USA report about potential oil spills involving pipelines south of the border is raising concerns about the risk of spills here.

The report, entitled Four Proposed Tar Sands Oil Pipelines Pose a Threat to Water Resources, is an analysis of publicly available data from sources such as the U.S. Pipeline and Hazardous Materials Safety Administration and the Center for Biological Diversity.

It states that TransCanada, Kinder Morgan, Enbridge and their subsidiaries have seen 373 hazardous liquid spills from their U.S. pipeline networks since 2010.

Greenpeace says a total of 63,221 barrels of hazardous liquids were released during that time period, including Enbridge's 20,082-barrel diluted bitumen spill that devastated Michigan's Kalamazoo River in 2010.

The report states the U.S. crude oil pipeline system as a whole has averaged one significant incident and a total of 570 barrels released per year, per 1,000 miles of pipe, over the past 10 years.

This map produced by Greenpeace shows the locations for 373 U.S. hazardous liquids pipeline spills from 2010 to present for TransCanada, shown in green, Kinder Morgan (purple) and Enbridge (blue). It cites data from U.S. Pipeline and Hazardous Materials Safety Administration and the U.S. Energy Information Administration. (Greenpeace)

Using average oil spill incidence data, Greenpeace estimates the potential number of incidents over a 50-year lifespan. Based on historical data, the proposed Keystone XL pipeline could expect 59 significant spills over that period, it says.

This averages out to around one significant spill per year for the proposed 1,900-kilometre pipeline slated to transport oil from Alberta's oil sands to refineries off the coast of Texas.

'Pipelines consistently leak,' says author

"The main takeaway of the report is that pipelines consistently leak, so building more pipelines to transport Alberta's tar sands will inevitably increase the risk of a significant oil spill for communities along the pipeline routes," Tim Donaghy, a Greenpeace USA senior research specialist who authored the report, said in an email to CBC News.

"To me, if I was a community member living on any of these routes, alarm bells would be going off because I don't want to see a spill a week happening to me or any communities along that pipeline route," said Mike Hudema, a climate and energy campaigner with Greenpeace Canada.

"That's what Canadians can expect if these new pipelines are approved because this is the company's records in the U.S."

Greenpeace estimates Enbridge's Line 3 Expansion could see 51 spills over the same 50-year lifespan.

"These companies have an atrocious spill record in the United States and we shouldn't give them new opportunities to bring new spills and do more damage to new communities along these pipeline routes," said Hudema.

"What we always hear from pipeline companies and government is that they use state of the art technology that will ensure spills don't happen, that they're making a huge amount of progress and that they're the safest way to transport oil and communities don't have to worry…but what this report clearly shows is that communities do have to worry."

The head of the Union of B.C. Indian Chiefs, who is "vehemently" opposed to Kinder Morgan's Trans Mountain expansion project — which would see 890,000 barrels of oil shipped to the British Columbia coast daily — said he's not surprised by the report's findings.

"This underscores the urgency in regard to ensuring that we have a proper environmental regulatory process in place, which clearly does not exist at this point," said Grand Chief Stewart Phillip, who added that it's time governments live up to their pre-election promises.

"We know that there's no way to mitigate a catastrophic pipeline rupture or tanker spill. We're deeply disappointed that the Trudeau government did not follow through with completely revamping the Canadian Environmental Act process and the National Energy Board (NEB) approval process. Both were commitments he made during [the] election…. Now we need to declare a complete moratorium on all pipelines construction projects immediately."

'Very strict' regulations in Canada

A spokesperson for the National Energy Board said it's difficult to compare pipeline regulatory procedures in the U.S. to the Canadian regulatory process.

However, Darin Barter said the NEB safety requirements are extensive. In 2016, the NEB tracked 1.5 incidents per thousand kilometres of pipeline in Canada, with the total amount of crude oil spilled equalling 50 barrels.

"Our regulations are very strict and that's why we see very few incidents on any regulated pipelines in Canada," said Barter.

"From an NEB perspective this is something we take very seriously. The companies who we regulate have a strong track record of very few spills and when they do occur they [companies] report it immediately and we address those immediately."

The Canadian Energy Pipeline Association (CEPA) responded to the report, stating that safety and environmental protection is its number one priority.

"We collaborate and strive to operate to the highest safety standards, and are committed to improving safety, lessening environmental impacts and achieving operational excellence now and into the future," it said via a statement.

The association says over the last 10 years, its members have maintained a 99.999 per cent safety record.

"While significant pipeline incidents are rare, exhaustive planning and ongoing practice ensures effective and efficient emergency response and remediation," it said.