What prompted the recall at Able Labs?

USA Today examines the strange case of Able Laboratories, the generic drug maker which pulled all of its drugs from the market in one of the biggest recalls ever to hit the business. But a month after the recall, after Able's stock has fallen 86%, little is known about what prompted the recall or what Able needs to do to fix the problem. Some of the most important unanswered questions lie with the FDA, which repeatedly inspected Able's facilities without raising any concerns.

- read this story from USA Today