The State Department issued its final environmental impact statement Friday for a controversial oil pipeline stretching from Canada to Texas, affirming earlier findings that its construction and operation will have “limited adverse environmental impacts.”

The assessment moves the $7 billion Keystone XL pipeline closer to fruition, though State Assistant Secretary for Oceans, Environment and Science Kerri-Ann Jones emphasized the analysis “is one piece of the information that will be considered” in making a final decision on the permit by the end of the year.

The department will have to conduct a 90-day review of whether the project is in the “national interest” before deciding whether to allow the pipeline to go through.

“This is not the rubber stamp for this project,” Jones told reporters. “It should not be seen as a lean in any direction, either for or against this pipeline.”

Still, the conclusion of the 2 1/2-year-long review is significant because the primary objection raised against the pipeline is its potential environmental impact — during construction and in case of ruptures during operation — on wildlife, land and drinking water supplies.

In addition, the proposed pipeline, which could transport as much as 500,000 barrels of crude oil a day from Canada’s “tar sands” or “oil sands” fields to refineries in the Gulf Coast, has sparked an outcry from environmentalists in both countries on the grounds that the extraction of oil will increase emissions linked to climate change.

Oil sands contain a viscous oil called bitumen in formations of sand, clay and water, and to extract it, companies expend more energy and water than they do to tap other crude deposits.

Activists have mounted daily sit-ins for a week at the White House to protest the project, resulting in 376 arrests so far.

Jones said State officials concluded “there would be no significant impact to most resources along the proposed pipeline corridor,” though she added some American Indian culture resources and the endangered American burying beetle could be affected. The pipeline’s sponsor, TransCanada, will work with American Indian tribes to monitor and minimize the project’s impact and had proposed measures to compensate for any toll its activities could have on the imperiled beetle, she said.

State Department officials looked at several options, including scrapping the project altogether and moving it to a different location. “The agency-preferred alternative is the proposed Project with various and minor route realignments,” officials wrote in the executive summary of the final environmental analysis.

TransCanada issued a statement saying the assessment, which is more than 1,000 pages long, “reaffirmed the environmental integrity of the project.”

“Today’s Final Environmental Impact Statement continues to demonstrate the focus on safety and the environment that has gone into the development of this critical North American pipeline,” said Russ Girling, TransCanada’s president and chief executive officer.

National Wildlife Federation energy policy adviser Ryan Salmon questioned aspects of the report, noting that it anticipates between 1.78 and 2.5 spills a year even though a smaller section of Keystone pipeline that opened last year has already experienced 14 spills.

“There’s an obvious discrepancy there,” Salmon said. “To our knowledge, they never actually worked with the Pipeline and Hazardous Materials Safety Administration on a study to determine whether diluted bitumen poses increased risks for pipeline safety.”

Federal officials said minor spills were more likely to occur during the startup phase of the pipeline.

Current oil sands production, which is located in a 232-square-mile area in Alberta, accounts for 49 megatons of carbon dioxide equivalent a year, according to the Canadian government. That is more than the total amount of CO2 emitted annually by the city of Chicago. These emissions are expected to rise to 92 megatons by 2020, as Canada doubles its tar sands production.

State officials concluded that although oil sands extraction is more carbon-intensive, the pipeline project would not affect Canadian production because companies there would simply ship their heavy crude through other forms of transportation if the pipeline didn’t exist.

They also noted in the assessment that the 1,700-mile oil pipeline from Alberta to the Gulf Coast would help meet America’s long-term need for crude oil.

“Although there is sufficient pipeline capacity from Canada to the U.S. in general to accommodate projected additional imports of Canadian crude in the short to medium term, there is extremely limited pipeline transport capacity to move such crude oils to Gulf Coast refineries,” the report states.

Rep. Edward J. Markey (Mass.), the top Democrat on the House Natural Resources Committee, wrote a letter to Secretary of State Hillary Rodham Clinton on Friday complaining the department failed to fully analyze the impact on wildlife along the corridor such as the endangered whooping crane.

The department announced it would hold 13 public meetings in nine cities between Sept. 26 and Oct. 6 to get feedback on whether the pipeline should win federal approval. The sessions will take place in several states the project will traverse, including Montana, Nebraska, Kansas and Texas.