TransCanada, an Alberta-based energy company, recently shot back at criticism about its pipeline route choice from U.S. senators.

The company said that the route of its 1,661-mile-long Keystone XL pipeline was chosen to have the smallest impact possible, reports Platts.

"Our focus was to reduce the overall footprint of the route by avoiding environmental, engineering and economic impacts," firm spokesman Terry Cunha told the news source in an email. "Route choices also took into account potential impacts on wildlife, archaeological resources, aboriginal settlements, crops and protected areas."

Seven Democratic senators wrote a letter to Secretary of State Hillary Clinton to express concern about the potential environmental impact of the pipeline, pointing to the recent ExxonMobil spill in Montana, reports The Hill.

The lawmakers are hoping that the State Department will further review the proposed pipeline, which would carry oil from Canada to Texas.

"We believe that the DOS should work with the [Pipeline and Hazardous Materials Safety Administration] to more thoroughly review the safety of the proposed Keystone XL pipeline and put in place sufficient safety measures," the letter stated.

According to Cunha, the pipeline has support from four trade groups and 14 American senators.

TransCanada is expected to release its second-quarter financial results on Thursday, July 28, which could potentially affect oil stocks.