Yesterday’s Washington Post has an in depth—and very depressing—piece about Medicare fraud. The piece focuses on scammers taking advantage of Medicare’s payment systems to buy unnecessary motorized wheelchairs and scooters for Medicare enrollees and stick American taxpayers with the bill.

Medicare’s payment system is designed to pay bills within 30 days of receipt; the system receives 5 million claims daily. Due to the huge volume of payments, Medicare only reviews a very small percentage, 3 percent, before the payment is made. Instead, payments are reviewed after they are processed, but even then not all are subject to oversight and review.

That system design invites fraud and scammers are able to take advantage. The Washington Post describes it as an “honor system.” The lack of upfront investigations costs taxpayers billions annually in fraud and wasteful payments.

But even worse than Medicare’s lax oversight is that officials knew about the fraud regarding wheelchairs and still didn’t act. According to the Washington Post,

Now, the golden age of the wheelchair scam is probably over.

But, while it lasted, the scam illuminated a critical failure point in the federal bureaucracy: Medicare’s weak defenses against fraud. The government knew how the wheelchair scheme worked in 1998. But it wasn’t until 15 years later that officials finally did enough to significantly curb the practice.

This problem was widespread. Medicare has spent $8.2 billion on power wheelchairs since 1999 for an ever-increasing proportion of enrollees. Records suggest “that at least 80 percent of claims were ‘improper.’”

Before the fraud had taken off, the chairs were rare: One study estimated that in 1994, only 1 in 9,000 beneficiaries got a new wheelchair.

By 2000, it was 1 in 479.

By 2001, it was 1 in 362.

By 2002, it was 1 in 242.

In 2012 up to 219,000 Medicare recipients received motorized wheelchairs, 1 in 235 patients, worse than in 2002. In 2013 only 124,000 individuals, 1 in 400 patients, received power wheelchairs from Medicare.

Medicare is slowly getting the issue under control; it is just 15 years too late.