Despite years of major media headlines and political infighting over the Keystone XL pipeline, half of all Americans still haven’t heard of the project, according to a recent public opinion survey.

TransCanada’s $5.3 billion Keystone XL pipeline project has been in the news for years. Since the project was first proposed in 2008, it has been targeted by environmental groups and covered by local newspapers and national news media like the U.S. World News Report and the Wall Street Journal. Countless articles have been written about the pipeline, which would transport 830,000 barrels of tar sands crude oil each day from Canada to the Gulf of Mexico.

Despite the robust coverage, a recent national poll conducted jointly by researchers at Yale University and George Mason University found that half of all Americans still haven’t heard of the Keystone XL pipeline.

“Half of Americans (50%) have never heard of the Keystone XL pipeline, which would transport crude oil from the Canada tar sands to Texas. Moreover, few Americans say they are following the issue closely (18%). However, among those Americans who have heard of the Keystone pipeline, about two in three support the project (63%),” write the researchers, who based their conclusions on interviews with a nationally representative sample of 1,045 adults.

Researchers did not offer an explanation as to why half of Americans have not heard about the pipeline project.

The Obama administration must approve construction of the Keystone XL pipeline because it crosses an international border. However, TransCanada has moved forward with a portion of the pipeline that is located entirely in the United States. The Canadian Press reports that the U.S. leg of the project is 70 percent complete. If the full pipeline is completed, the project will begin in Alberta, Canada, stretch 1,179 miles through six U.S. states, and terminate at oil refineries along the Gulf Coast.

Environmental groups have warned against developing the Keystone XL pipeline because of the damage it could cause to the environment.

“(The pipeline) would cut through America’s heartland and put people and wildlife at risk from toxic oil spills, polluted water and more,” warns the National Wildlife Federation. “Perhaps most dangerously, Keystone XL would drive development in Canada’s tar sands region, one of the biggest threats to our global climate.”

Some groups have organized public protests urging the Obama administration to block construction of the Southern leg of the pipeline.

“There is a reason that they are willing to put their bodies on the line. The long-term plan for the oil industry in Canada is to increase output to 9 million barrels a day. The pipeline is the key to facilitate that. Nine million barrels of the world’s dirtiest oil is something our world can’t handle,” Daniel Kessler, a spokesperson for the environmental organization 350.org, told Mint Press News.

So far, roughly 1,500 people have been arrested in public demonstrations and acts of civil disobedience against the pipeline. Some have tied their bodies to construction equipment and blocked roads in Oklahoma to delay construction.

“At least 1,500 people in total now have been arrested and those numbers will only increase,” Kessler said.