WASHINGTON -- The "world's most expensive gas station" might still be operating -- or maybe not. The Department of Defense says it has no current information about the taxpayer-funded project, or any of the others that were part of its $766 million program to stimulate economic development in Afghanistan.

According to letters between the top government watchdog in Afghanistan and a DoD official, the Pentagon has had no oversight of outcomes for its Task Force for Business and Stability Operations programs since the task force ended in March. The correspondence is included in a scathing report released Monday from the Special Inspector General for Afghanistan Reconstruction about a gas station in northern Afghanistan that investigators say cost 140 times what it should have.

"DoD charged the American taxpayer $43 million for what is likely the world's most expensive gas station," Special Inspector General for Afghanistan Reconstruction John Sopko said in an email response to Stars and Stripes. "DoD spent nearly $800 million ... but now they claim no one knows anything about it."

The compressed natural gas station, built in the city of Sheberghan, was part of a plan to persuade Afghan drivers to switch from gasoline and to encourage international companies to invest in Afghanistan's nascent natural gas industry. The original contract to build the station was for $3 million. SIGAR's report says similar gas stations in Pakistan cost about $300,000.

"The Sheberghan facility is yet another example of this Administration's reckless spending," Rep. Jason Chaffetz, R-Utah, chairman of the House Committee on Oversight and Government Reform, said in an email to Stars and Stripes. "DoD has no explanation or documentation as to why it cost a massive $43 million to construct a compressed natural gas station in Afghanistan."

The DoD did not respond to a request for comment.

Sopko began the review in May. In a letter to Defense Secretary Ash Carter, Sopko said, "On its face, this project does not seem feasible for several reasons." He went on to ask questions on how much revenue the station has provided to the Afghan government, which provides oversight for the station, and whether there was a feasibility study. A defense official responded June 17, saying the program had closed about three months earlier and Carter's office could no longer answer questions about it.

"With respect to the detailed questions that you have posed regarding the Downstream Gas Utilization project, the closure of the TFBSO in March 2015 and departure of all of its employees have resulted in the Office of the Secretary of Defense (OSD) no longer possessing the personnel expertise to address these questions or to assess properly the TFBSO information and documentation retained by (Washington Headquarters Services) in the OSD Executive Archive," Principal Deputy Undersecretary of Defense for Policy Brian McKeon wrote in the response to Sopko.

In more recent letter dated Oct. 9, McKeon said defense officials would allow SIGAR officials to view task force documents "with appropriate security safeguards; such safeguards are necessary due to SIGAR's actions that revealed Personally Identifiable Information in an unrelated incident," though he does not specify the incident.

SIGAR officials say Defense Department officials would only allow investigators to view documents under DoD supervision and that the Defense Department Freedom of Information Act office would have to redact documents before releasing them.

"We continue to provide complete and unfettered access to TFBSO documents to SIGAR through the reading room managed by the Washington Headquarters Services," Pentagon spokesman Lt. Col. Joe Sowers said in an email response to Stripes. "Further, we have offered to assist SIGAR in locating and contacting any former TFBSO personnel they wish to interview."

The legislation that created the special inspector general's office does not call for officials to redact documents before releasing them to investigators. SIGAR officials said that DoD's response to their request was the first time the Defense Department made that demand, which Sopko declined, calling accusations of mishandling personal information in a separate investigation "a red herring."

"Under the circumstances, DoD's position that it has no knowledge about this $800 million program is startling and unconvincing," according to the report. "It is also a major concern because TFBSO was DoD's principal vehicle for stimulating private sector investment in Afghanistan to build a stable and growing economy."

This is not the first controversy to dog the task force, which began in Iraq in 2006 and moved to Afghanistan in 2009. Its goal was to help Afghanistan harness its substantial untapped natural resources, which the task force said were potentially worth $1 trillion.

In December, SIGAR said it was reviewing reports of "imprudent spending" and "profligate travel by employees and contractors," including months-long gem training programs in India and trips to Paris and Milan.

A SIGAR report released in April said nearly $500 million in U.S. investment in Afghanistan's natural resource industries was at risk because of poor coordination between the task force, the U.S. Agency for International Development and the State Department.