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Democratic presidential candidate Bernie Sanders is proposing to wipe out an estimated $81 billion in past-due medical debt. Up to 80 million Americans could be impacted. "People definitely need to have their debt either forgiven or negotiated lower, so they can afford it without a hardship," said Craig Antico, the co-founder of RIP Medical Debt, which buys and forgives medical debt. Tweet Two-thirds of people who file for bankruptcy each year blame their health-care costs, according to one study. "People are one illness or accident away from financial ruin in this country," Antico said. Sanders' announcement on medical debt builds on his Medicare for All plan, and would likely be paid for with a tax on corporations based on their CEO compensation. In a recent town hall, a military veteran from Nevada told Sanders he was considering suicide due to his $139,000 in medical debt. CNBC spoke to people about how they fell into medical debt and how it shapes their lives.

Kathleen Herzig Source: Kathleen Herzig

KATHLEEN HERZIG couldn't walk 10 feet without becoming breathless. The 58-year-old blackjack dealer from Primm, Nevada, needed an aortic valve replacement in 2017 and wound end up staying in the hospital for over a month. Herzig didn't have health insurance through her job, and now she has over $600,000 in medical debt. "It's horrible," she said. "I've never been in debt." She said her only way out is bankruptcy, but, she said, "I can't even afford to file at this point in time." She earns around $8 an hour, before tips. She's also worried that having a bankruptcy on her record would make it hard to get a higher-paying job. In the meantime, she's harassed by debt collectors and has become depressed, she said. She still doesn't have health insurance, and said she knows she should be going to a cardiologist but doesn't want to go deeper into debt. "There's no way I can get that done," she said. "I'm jeopardizing my life."

Diane Denton with her son and husband. Source: Diane Dent

Steve Aquino with his son and daughter. Source: Steve Aquino

STEVE AQUINO had always been healthy. The York, Pennsylvania, resident wasn't too worried, then, when one evening his right foot began to really hurt. Then other areas of his body — his shoulders, neck and back — began to really hurt, too. Soon he could barely turn his head. Even walking was hard. "It felt like someone was sticking a knife between my vertebrae and then twisting it," Aquino, 31, said. The software developer eventually lost his job, and had to go on disability insurance. Five years later, he still doesn't have a diagnosis. What he does have: thousands of dollars in medical debt from the flurry of tests and treatments he's needed. "I've been slammed with bills," he said. He's around $2,500 in the red, he said, and expects to rack up only more debt. "It's getting harder and harder to do normal things," he said. He has health insurance though his remote job, but his out-of-pocket expenses are still high. "It's just really depressing."