President Donald Trump announced Friday that the project for TransCanada to complete the Keystone XL pipeline has been approved. The approval comes in direct opposition to efforts made by the Obama administration to block the controversial project from going through.

The construction of this portion of the pipeline has been heavily debated in regard to environmental and economic impact. This week’s Political Focus will look at the pros and cons of this project and break down the debate that has been ongoing for over eight years.

What is the Keystone XL pipeline?

TransCanada, a North American energy company, created the Keystone pipeline, which, in total, is a 3,800-mile pipeline transferring oil from Canada to the U.S. The Keystone XL is the final piece of construction for the network and has been awaiting approval from the U.S. government since its original request for approval was filed in 2008.

The entire pipeline network runs from the oil sands of Alberta, Canada, to the gulf coast in Port Arthur, Texas. The Keystone XL portion would create a more direct route for oil through Montana, South Dakota, Nebraska, Kansas, Oklahoma and Texas. The project would require construction in all these states, except Kansas and Oklahoma, as it would join the current pipeline in Nebraska and break off again in Texas.

This more direct route would allow for more oil (approximately 800,000 additional barrels per day) to be pumped to the oil refineries on the Gulf Coast, where most of the North American oil industry is based.

What’s the economic debate?

Trump and other proponents say the project will be a job creator. The U.S. Department of State’s report from 2014 determined that the project would create 42,100 jobs, not including the estimated 10,400 seasonal jobs that would be created for construction.

Most of those jobs are a result of “spillover spending,” as workers would spend money on equipment as well as a variety of services that would only last the expected two years of construction. CNN’s Van Jones said the pipeline would create only 35 permanent jobs.

Additionally, more oil available from Canada means less dependence on the supply from Middle Eastern countries. This would, in theory, mean lower prices for consumers and less power to Middle Eastern countries in foreign policy negotiations.

Opponents argue that the pipelin wouldn’t actually have any effect on the energy dependence of the U.S. because Canada would use the pipeline to transport the oil, then export it to other countries. However, Politifact found that American refineries would be the “primary buyers of crude oil transported through the Keystone XL pipeline, by a vast margin.”

What’s the environmental debate?

According to CNN, the extraction process to access the crude oil in the oil sands of Alberta produces 17 percent more greenhouse gases than standard oil extraction processes. This is because, instead of coming from a well, the tar sand oil must be “essentially melted with steaming hot water before it can be refined.”

This further contribution to climate change is enough for environmentalists, as well as former President Barack Obama, to oppose the project. Environmentalists want the oil left in the ground.

However, as the Chicago Tribune’s Stanford L. Levin argues, blocking this project would not stop Canada from using this method to extract the oil. It would instead cause them to use other means to transport the oil, most likely rail transportation — which is argued to be less safe and worse for the environment than pipeline transportation.

Environmentalists also argue against the route of the pipeline because it runs through the Ogallala Aquifer, an underground deposit of water accessible by wells. This aquifer is a key source of fresh water and would be at risk for pollution if the Keystone pipeline ran through it. The U.S. Department of State report, however, concluded that impact on water quality would be limited.

What’s next?

Now that the project has been approved at the federal level, it awaits state approval in Nebraska. That decision is expected in September. Additionally, the plan surely awaits protests from more than just environmentalists. Native Americans have united over the issue of such oil pipelines in the past, and the Keystone XL route runs through the sovereign lands of some tribes.

Trump will now have to shift to another campaign promise in regard to the pipeline. He stated again just last week that, if the pipeline was approved, he would ensure TransCanada constructed it with American steel.

TransCanada has previously stated that roughly half of the pipeline would use steel made in the U.S.