LOS ANGELES (CBSLA.com) — Surprise medical bills have become a crippling financial problem for thousands of Californians with preferred provider organization plans, or PPOs.

“I’ve always paid my bills. I had excellent credit,” said Nancy Gomez of Glendale.

But these days, Gomez knows better than to apply for a loan or new credit card.

“I’m just afraid that I’ll be denied and, quite frankly, I think I will,” said Gomez, who is saddled with thousands of dollars in medical debt.

Charges she never saw coming.

“I am a fully insured person,” said Gomez, who has a solid medical plan, one that let her choose top-tier doctors to fix her bad back.

“I paid extra to have a PPO insurance,” said Gomez, who initially chose treatment with an Encino pain specialist.

“I researched him, made sure that he was in my network,” she said.

And, in fact, he was. Her initial visit cost just what she expected: a $40 co-pay.

“The doctor was very nice and told me, ‘Yes, I can definitely help you,’ ” she said.

Gomez went in for an epidural nerve block and a few weeks later says she was shocked and devastated to get an $18,000 bill.

Though the bill is totally legitimate, Nancy Kincaid says, “it’s rather alarming.”

Kincaid is with the California Department of Insurance and explains that, under current law, “it is legal to get these bills.”

Here’s how it happened:

When Gomez returned for the injection, she says “they directed me to go to the second floor, where the doctor would perform the procedure.”

The problem, she says, “he went upstairs to his surgical suite and that made him an out-of-network provider.”

There is no limit on what an out-of-network provider can charge.

“Increasingly, we’re seeing consumers getting these surprise bills,” said Kincaid.

Gomez’s ordeal was far from over. The epidural didn’t work, so she scheduled surgery.

“I made sure that the surgeon, that the hospital, were in my network,” she said.

Her surgery was a success and while she was home recovering, she says, she got another bill.

“I get a bill for about $9,000,” she said.

But while Gomez was on the table, “apparently there was an assistant surgeon who did not belong to my in-network provider list,” she said.

What’s more, she was billed again, explaining: “unbeknownst to me, the anesthesiologist was also out-of-network. … It put me into incredible debt.”

Gomez is not alone.

Consumer Reports says one in four Americans have been blindsided by surprise medical bills, charges from out-of-network providers who participated in their care without disclosing their fees, often without their knowledge.

“You meet your anesthesiologist literally 15 minutes before you go under the knife,” she said. “Even if you were to ask, ‘Are you in my network?’ what are you going to do, stop the surgery?”

Assembly Bill 72 is currently being considered in Sacramento. If passed, it would ensure that patients pay only in-network fees if they go to an in-network hospital. Doctors who are out-of-network would have to settle extra charges with insurance companies, not patients.

Gomez hopes her story encourages lawmakers to take action.

“I ended up paying what I could and then I was sent to collection and to this day, that’s where I am,” she said.

Click here for tips on how to protect yourself from surprise medical bills.

Story produced by Gerri Shaftel Constant, the medical producer for CBS2/KCAL9-TV.