DENVER -- Tens of thousands of uninsured patients could get hospital care under a bill signed Tuesday by Gov. Bill Ritter.

The new law generates funds through hospital provider fees and federal matching dollars to cover the cost of caring for uninsured patients.

Supporters said the measure will keep health care costs down and reduce the number of uninsured people seeking care in emergency rooms because they can go to their own doctor.

"The most expensive place to treat someone is in the emergency room," said Steven Summer, president and CEO of the Colorado Hospital Association. "What happens is (uninsured patients) go there because they don't have a physician."

The Colorado Hospital Association represents 90 hospitals and health systems across the state.

Ritter said the bill will provide coverage to nearly 100,000 Coloradans and provide some guarantee that hospital care is available to the other 700,000 Coloradans.

"This is the most significant health reform legislation in Colorado in four decades," said Ritter, who was surrounded by doctors and hospital officials.

Supporters said the Colorado Healthcare Affordability Act will allow the state to collect $600 million a year through a provider fee, allowing the state to get another $600 million in federal Medicaid matching funds.

Rep. Jim Riesberg, sponsor of the bipartisan bill, said the money will ultimately go back to hospitals.

"They'll probably get more back than what they put in, because that money is going to double," Riesberg told 7NEWS.

Ritter said there will be no increased cost to taxpayers, but opponents said no one knows how much the fees would cost or who would pay the estimated $600 million a year.

Republicans said someone will have to pay, and it will probably be passed on to insurance companies and consumers.

Ritter disagreed. "The bill is very clear that hospitals cannot bill this out, and the important thing to remember with the hospitals paying into this fund, there's also federal money that we draw down. We have a right to do that," Ritter said.

Republicans tried to cap the fees at $2,000 per patient per day, but Democrats refused to impose any cap, saying the state shouldn't limit the amount of federal money hospitals could receive.

Ritter said many of those issues will be handled by a 13-member oversight committee.

Summer said the new law is a step toward solving the state's health care crisis.

"This new law is not a silver bullet solution to all of our state's health care problems, but it is certainly a giant step forward," he said.

"It means a significant number of people, perhaps one-fourth of those today who have no insurance, will have insurance for themselves and their families, Riesberg said.

He added health care costs could be reduced for everyone.

Summer agreed. "A great deal behind the increase in costs today has been the underinsured, people who've been using the hospital and not adequately paying for it, or the uninsured," he said.

"For those who have insurance, they should be able to save money, and insurance premiums should either stop rising or even go down because the hospitals will not be transferring uncompensated care to those who are paying for care," Riesberg explained.

Russ Johnson, who heads the San Luis Valley Regional Medical Center, said the current healthcare system is not sustainable.

"In many rural communities, the hospital is the only healthcare provider," he said.

The new law is welcome news to people like Chancellar Williams, 32, a graduate student living in Denver without health insurance.

"It was just a situation where the cost was out of reach for me," Williams said

Williams explained he uses extra caution while skiing and snowboarding and turns to the Internet for treating a cold. He's hopeful to land a permanent job following graduation, but knows the economy could delay plans.

"It's just nice to know, until I can make that happen, I'm covered and there's a safety net there," Williams said.

A 13-member advisory and oversight committee with help implement the law. The plan still must be approved by the federal government.