The U.S. State Department's Office of the Inspector General has launched a special investigation of the Keystone XL pipeline approval process in response to complaints that the government's review was prejudiced by bias and conflicts of interest.

State Department Deputy Inspector General Harold Geisel issued a memorandum on Friday, Nov. 4., stating he would open the investigation in response to a Congressional request. Geisel wrote that he aims to determine to what extent the department and all other parties involved complied with federal laws and regulations relating to the Keystone XL pipeline permit process.

The investigation could likely delay the Obama administration's decision on whether to approval the $7 billion, 1,700-mile pipeline, which would transport crude sand tars from Alberta, Canada to refineries on the Gulf Coast. The State Department had initially indicated the decision would be made by the end of the year, although officials recently conceded the process may take longer.

Congress Requests Independent Inquiry

Thirteen members of congress -- including Sen. Bernie Sanders, I-Vt., Sen. Sheldon Whitehouse, D-R.I., and Rep. Dennis Kucinich, D-Ohio -- requested an independent inquiry into the pipeline's pending decision in response to multiple reports that the State Department allowed the pipeline developer, TransCanada, to select Cardno Entrix to conduct an environmental assessment of the project even though the two companies had a pre-existing financial relationship.

The assessment ultimately concluded the pipeline would have a minimal environmental impact. Several environmental organizations and scientists have warned that the pipeline, which would go through Nebraska, could contaminate the state's Ogallala aquifer, a primary source of drinking water for almost two million people in that region.

The Environmental Protection Agency has raised objections to the project and has said the State Department needs to conduct further research on the impact of groundwater and air pollution, as well as pipeline safety.

Several parties have also raised objections to Secretary of State Hillary Clinton's close ties to Paul Elliot, a senior staff member in her 2008 presidential campaign who is now lobbyist for TransCanada.

A TransCanada spokesman told The New York Times it welcomed an independent review from the Inspector General so that these latest claims by professional activists and lawmakers who are adamantly opposed to our pipeline can be addressed.

Senate Environment and Public Works Committee Chairwoman, U.S. Sen. Barbara Boxer, D-Calif., is pressing Clinton for more details surrounding the State Department's review of the pipeline, The Hill reported. Boxer reportedly sent a letter to Clinton questioning whether the State Department's environmental assessment fully investigated the possible ecological impacts of the tar sands pipeline and requested that the State Department provide information into whether Cardno Entrix's employment for the review was in full compliance with the National Environmental Act and other laws.

Following the nation's worst oil spill and at a time when the effects of global warming become more apparent every day, it is imperative that we have thorough and objective environmental assessments so that the public can fully understand the impacts of proposed projects, Boxer wrote.

Environmentalists Protest

Environmental activists have held multiple demonstrations in front of the White House to protest the Keystone project since late August. On Sunday, thousands of activists circled the building demanding the President Barack Obama kill the project, leading to the arrest of about 1,200 people.

In addition to compromising drinking water supplies, environmentalists claims the project will increase excessive greenhouse emissions, harm local wildlife and increase the nation's dependence on fossil fuels that contribute to climate change.

However, proponents argue the project would create thousands of new jobs and reduce oil imports from the Middle East and other foreign regions.

CORRECTION: A previous version of this article stated Sen. Bernie Sanders was from Virginia (Va.) Sanders represents Vermont.