Environmentalists are again taking aim at the company that proposed the Keystone XL pipeline this time for another of its projects they fear would send hundreds of supertankers laden with crude oil down the Atlantic coast to refineries in Texas and Louisiana.

TransCanada is behind the Energy East pipeline project, a 4,600km pipeline, or nearly 3,000 miles, that would carry crude oil from tar sands in Western Canada to the East Coast, where it would then be shipped to refineries along the Texas Gulf Coast. When completed, the project would carry 1.1m barrels of crude oil every day from Alberta and Saskatchewan to refineries in Eastern Canada.

Plans call for converting a natural gas line for part of the route and then building a new pipeline in Alberta, Saskatchewan, Manitoba, Eastern Ontario, Québec and New Brunswick to connect to the existing pipeline.

The Natural Resources Defense Council, Sierra Club and other environmental groups are concerned about potential spills of tar sands diluted bitumen along the route in Canada that goes over thousands of rivers, streams and lakes. They also warned a spill along the east coast could prove devastating to communities that depend on tourism and fisheries and are not prepared to handle an event of this kind.

The groups held a conference call Tuesday with the media, in releasing a report , “Tar Sands in the Atlantic Ocean: Transcanada’s Proposed Energy East Pipeline,” that lays out their case against the project.

“What we have is a proposal to move nearly 300 super tankers down the eastern seaboard, and we don’t have the techniques and technology to contain and clean a spill of tar sands diluted bitumen should one happen,” said Anthony Swift, the Canada project director for the Natural Resources Defense Council.

TransCanada said that the project would adhere to stringent safety standards and that it would be the responsibility of its customers of where they ship the oil, noting that “it does not own or operate ships for the delivery of oil.”

“Safety remains our top priority,” TransCanada spokesman Jonathan Abecassis said in an email to The Associated Press. He said the port in New Brunswick “will have a number of preventive safety measures” including the use of trained pilots and advanced navigational and docking technologies.

“We are working in collaboration with local authorities and first responders during the development of our emergency plan to ensure that the plan is adapted to local circumstances with resources placed strategically across the route to react quickly in the unlikely event of an emergency,” he said.

Abecassis said the project is being reviewed by the National Energy Board in Canada. Environmentalists are hopeful the United States will express its opposition to the project during this review process and enact a ban on the shipment of tar sands in US waters.

The project comes less than a year after President Barack Obama rejected the Keystone XL project following seven years of political wrangling, arguing it would have undercut US efforts to clinch a global climate change deal. The Paris agreement last December aims to keep the global temperature rise below 2 Celsius (3.6F) compared with preindustrial times.

Environmentalists are hoping the same grassroots success they had with Keystone will bring down the Energy East project. In a sign they may use some of the same tactics, the National Resource Defense Council has already launched a petition against the project that highlights the role tar sands play in worsening global warming.

“We’re here today because the threat of climate change is increasingly dire, and we have a critical but narrow window of opportunity to take action,” Sierra Club’s Cathy Collentine said. “That includes action to stop tar sands infrastructure from being built and to take action to ban the transport of tar sands in tankers that would increase the threat to our communities, environment and our climate.”