Few people realize that the loans they take out to pay for their education could eventually derail their careers. But in 19 states, government agencies can seize state-issued professional licenses from residents who default on their educational debts. Another state, South Dakota, suspends driver's licenses, making it nearly impossible for people to get to work. Firefighters, nurses, teachers, lawyers, massage therapists, barbers, psychologists and real estate brokers have all had their credentials suspended or revoked. Determining the number of people who have lost their licenses is impossible because many state agencies and licensing boards don't track the information. Public records requests by The New York Times identified at least 8,700 cases in which licenses were taken away or put at risk of suspension in recent years, although that tally almost certainly understates the true number. With student debt levels soaring - the loans are now the largest source of household debt outside of mortgages - so are defaults. Lenders have always pursued delinquent borrowers: by filing lawsuits, garnishing their wages, putting liens on their property and seizing tax refunds. Blocking licenses is a more aggressive weapon, and states are using it on behalf of themselves and the federal government. Tennessee is one of the most aggressive states at revoking licenses. From 2012 to 2017, officials reported more than 5,400 people to professional licensing agencies. Many - nobody knows how many - lost their licenses. Some ... lost their careers.