SACRAMENTO (AP) — Jiggy Athilingam was riding a bicycle in San Francisco five years ago when suddenly she was on a bed in the hallway of a hospital.

“What happened?” she asked.

A cracked helmet told the story of her memory loss: She had been hit from behind by a car. She spent 22 hours in a hospital emergency room, getting CT scans and painkillers before they sent her home. Four months later, as a Ph.D student living on a $35,000 stipend, she got a bill for $41,000.

She had the same question: What happened?

Athilingam had two forms of health insurance and assumed it would pay for most of her bills. Plus, California has laws protecting patients from surprise medical bills. But there is a loophole for emergency rooms. And because Athilingam was treated at a hospital that was outside of her health insurance company’s network, she got hit with a surprise bill — a common story in the country’s complex health care system.

Lawmakers in Congress and state legislatures across the country have proposed bills to fix problems like this, especially in emergency situations where patients often cannot choose what hospital treats them. While most people agree patients should not have to pay in these situations, there’s little agreement on who should.

It’s a debate now playing out in the California Legislature that’s pitting insurance companies and hospitals against each other.

A bill by Assemblyman David Chiu, a San Francisco Democrat, would make sure emergency patients never pay more than their copays or deductibles, even if they are treated at an out-of-network hospital. But the bill would cap what hospitals can charge insurance companies, because advocates and some lawmakers view hospitals as a monopoly with too much power over prices. Chiu said his goal is to keep insurance rates from skyrocketing.

“It’s not enough just to say the patient won’t get a whopping bill if the hospital is going to send an enormous bill to the insurer, who then simply turns around and raises your premiums a few months later,” Chiu said.

The California Hospital Association strongly opposes that approach, and advocates worry their position could doom the bill’s chances of passage this year. A key test will be Wednesday, when the Senate Health Committee has scheduled a hearing on the proposal. This is the last week for bills to clear policy committees if they hope to reach the floor before lawmakers adjourn for the year in September.

Carmela Coyle, chief executive officer of the hospital association, said 38% of California’s more than 400 hospitals already lose money. The real monopoly, she argues, are the insurance companies. Four insurance companies control 86% of the large group insurance market, while five companies control 94% of the individual market.

“(The proposal) puts money into the pockets of insurance companies and does not make care more affordable for consumers,” Coyle said. “There is nothing in this bill that requires insurance companies to pass any savings associated with rate-setting on to consumers.”

California Association of Health Plans spokeswoman Mary Ellen Grant said insurance companies have long opposed these types of surprise medical bills, saying “it’s unfair to put consumers in the middle of payment disputes that should be handled by health plans and providers.”  She said the association, which represents 47 health plans that cover more than 26 million people, looks forward to working with lawmakers on the proposal, though she declined to offer specifics about what changes insurers want to see.

The group has advocated for consumer protections for decades, she said.

The proposal narrowly passed the state Assembly earlier this year. Chiu said CEOs from the state’s largest and most profitable hospitals have been calling lawmakers asking them to oppose the bill, an effective strategy because hospitals are major employers in most districts. Plus, records show the California Hospital Association’s political action committee spent more than $350,000 last year.

For Athilingam, she said it took two years to resolve her hospital bill, mostly with the help of the University of California-San Francisco, where she had insurance. Now 29, she works for a voting rights organization and has helped ask lawmakers to pass Chiu’s bill.

“There was no way that someone can pay that much money when you have insurance,” she said. “This is not the way it’s supposed to work.”