TransCanada's proposed Keystone XL oil pipeline may be at risk of attacks that might threaten water supplies to a large number of households, a new report from lobbying group NextGen Climate has claimed.

Writing in the report released on June 4, Dave Cooper, an ex-Navy Seal and a participant in the mission that eliminated Osama bin Laden, warned that remote pump stations along the pipeline could be destroyed with just four pounds of explosives. The most vulnerable part of the pipeline will be the one running along the northern Great Plains, he noted.

Cooper estimates that organized bomb attacks along Keystone's route might cause an oil spill of more than 68,000 barrels of oil that could leak into aquifers and make it especially hard to clean up, Reuters reported. The worst case scenario that the report describes predicts that some 172,000 barrels of oil could be spilled from the pipeline.

Attacking or conspiring to attack pipelines in the United States is not a common occurrence, Reuters noted. However, the risks should not be underestimated, especially after a 2012 report released by the Congressional Research Service which stated that pipeline IT systems were vulnerable to cyber attacks and hackers were able to cause explosions or spills through them.

NextGen Climate is a political group led by environmental activist and billionaire Tom Steyer, who has been quite outspoken in his opposition to the construction of Keystone XL, the news service said.