U.S. troops are set to withdraw from Afghanistan this year, but there's one American agency that still has what may be an impossible challenge, making sure the distribution of $15.3 billion in U.S. aid for the Asian nation isn't wasted or used in corrupt ways. If history is any guide, that is a tough job.

Two years ago, the U.S. Defense Department paid $486 million to purchase 20 military transport planes for the Afghan Air Force. After flying just 234 of 4,500 required hours, the planes, which didn’t have the necessary spare parts and were described by pilots as "death traps," were sold as scrap metal for 6 cents per pound.

“We’re still trying to find out why and who bought those things,” John Sopko, special inspector general for Afghanistan reconstruction, recently told International Business Times.

Broken planes are the least of Sopko’s worries. His office, known by its acronym Sigar is responsible for keeping an eye on more than $104 billion allocated by the United States for Afghanistan aid and has uncovered millions in waste through mismanagement, fraud and corruption. Sigar has exposed fraud as big as $300 million meant for Afghan police salaries that went missing and shoddy contracting that ended with a $456,000 training complex that “melted.”

As U.S. troops are set to withdraw from Afghanistan this year, Sopko’s team is settling in for the long haul. According to a Sigar report released Thursday, there is still $15.3 billion left to spend, and the office is trying to impose changes to ensure that the money gets where it needs to go.

“There is so much money pushed out so quickly, and the contracting officers are rated on how much money they put on contract, not whether the thing works,” he said.

Plus, most major decisions for Afghanistan’s reconstruction are made in Washington, D.C., Sopko said, and so don’t always translate on the ground. He noted that the office once got a complaint that brand new roads were falling apart. At first it seemed like the contractors had made a mistake, but the real problem was the American guidelines that didn’t match the situation.

“Many times, we don’t talk to the Afghans before we build something or create a program,” he said. “We don’t ask them whether they want it or need it. That’s a problem.”

Another example he mentioned was a $36 million state-of-the-art building project. The entire thing was as large as two football fields and had all the latest equipment and technology -- but nobody wanted it.

“It would have looked great in New York or D.C. or Brussels,” Sopko said. But it wasn’t in any of those cities. It was built at Camp Leatherneck, an Afghan Armed Forces base in Helmand province, and was left abandoned.

“New tables, new chairs, phones, all this stuff was never used,” Sopko said. “The general who was running the surge said ‘I don’t want it, I won’t use it,’ his boss said ‘we don’t want it, we won’t use it,’ and some general back in Washington said ‘meh, build it.’”

All these issues don’t even touch on one of the biggest problems, according to Sopko, which is the anti-narcotics program. Despite spending billions trying to eradicate the lucrative opium trade that funnels money to the Taliban and other insurgent groups, opium production is at an all-time high.  

But of course, bringing all these problems to light is Sopko’s job, and there has been serious progress in addressing these issues. Last month the office noted than 75 percent of its recommendations have been implemented.

Plus, after more than a decade of working on the ground, Sigar has been making strong connections. Sopko said that the citizens of Afghanistan are just as likely as government employees to point out mistakes. The office has a 24-hour hotline that operates in Dari and Pashto, and its Facebook page has more than 27,000 likes.

These resources and connections are going to help them keep an eye on the $15.3 billion left to spend, which is bound for seven major reconstruction funds. This includes $4.1 billion for the Afghanistan Security Forces Fund, which provides assistance, equipment and training to Afghan security forces, $10 million for the Commander’s Emergency Response Program that’s aimed at empowering local leaders and $110.1 million for drug intervention activities.

Unlike other U.S. agencies, the agency’s only mandate is Afghanistan, so they won’t be pulled onto other conflict areas, and instead are required to stay until there is less than $250 million left to spend, though how long that will take is unclear and Sopko wouldn’t put an exact date on it.

“We’ll be here until the lights go out,” he said. “And that could be a long time.”