Part of the controversial Keystone Pipeline was shut down earlier this week in North Dakota after approximately 350,000 gallons of crude oil was leaked, impacting a half-acre of wetland in the state. The spill, which was the second large one in two years and one of the largest in a decade, has drawn scorn from presidential candidates and environmental groups.

TC Energy, the operator of the pipeline, reported a drop in pressure Tuesday, prompting the pipeline to be shut down.

The company said in a statement that "We are establishing air quality, water and wildlife monitoring and will continue monitoring throughout the response. There have been no reported injuries or impacted wildlife."

The site is not in the vicinity of residences and the wetland is not a source of drinking water.

Politicians and environmental rights groups have criticized the Trump administration for the leak and have called for green energy alternatives.

Democratic presidential candidate and Massachusetts Sen. Elizabeth Warren said that "the Trump administration has pushed construction of the Keystone XL pipeline despite the known environmental and public health risks. North Dakotans deserve better than this. We need clean energy to protect our public lands and waters."

Another leading candidate, Sen. Bernie Sanders of Vermont, took to Twitter to condemn the pipeline and vowed to shut it down if elected.

A Democratic candidate for Congress in Arizona, Dr. Hiral Tipirneni, said in response to the leak that "Solar power doesn't spill. Wind power doesn't spill. Geothermal doesn't spill. We must move towards clean, renewable energies that don't threaten our land, water supplies and indigenous communities."

"When we are talking about what could happen or the risk that is posed by oil spills, we have yet another illustration here in North Dakota about what can happen," said Catherine Collentine, associate director of the Sierra Club's Beyond Dirty Fuels Initiative. "It's something that we need to be looking very closely at given the number of water crossings and the route of the proposed Keystone XL pipeline."

Environmental group Greenpeace USA said that the spill was "brought to you by the corporation that wants to build the much larger #KXL pipeline and have it cut right through the Midwest."

The Obama administration rejected TransCanada's application to build the Keystone XL pipeline in 2015, which resulted in criticism from Republican leaders at the time. In March, President Trump granted permission for the construction of the Keystone XL pipeline, saying that it is good for the environment and that it creates jobs.

The Keystone Pipeline System runs from Alberta, Canada, to refineries in Illinois and Texas, as well as to oil tank farms and an oil pipeline distribution center in Oklahoma. It can handle about 23 million gallons daily.