Up to one-third of Dallas-area residents don't have health insurance, and the number is rising. Everybody in North Texas pays the cost, through taxes and higher insurance costs – as much as an estimated $1,800 per family.

Illegal immigrants pump up the numbers. But even if there weren't any here, Texas still would virtually lead the nation in percentage of residents without health insurance, according to both conservative and liberal researchers. And Dallas County is close on Harris County's heels as the major metro county with the lowest rate of health insurance coverage.

"The cost is borne by those of us who have insurance to perhaps a greater extent than people recognize," said Eduardo Sanchez, vice president and chief medical officer of BlueCross BlueShield of Texas, the state's largest health insurer. "It's borne by all of us as taxpayers at local, state and federal levels."

Sanchez, a former state health commissioner, said people insured through their jobs pay for the uninsured again in the workplace, through higher premiums and eroding benefits – particularly if they're employed by small businesses.

A "vicious circle" of higher hospital prices, generated by costly emergency room care of the uninsured, drives up insurance premiums for employers, he said. Every year, that causes a few more bosses to drop coverage of their workers, he added.

"Now you have a higher number and percentage of uninsured," Sanchez said, and the downward cycle begins anew.

The state's demographer projects that nearly 36 percent of Dallas County residents under age 65 will be uninsured next year. In the six surrounding counties, 27 percent will lack coverage.

Officials at Baylor Health Care System in Dallas said they charge insured patients 150 percent of actual costs to cover charity care of the uninsured and underpayment by Medicare, the federal program for seniors and the disabled. Gary Brock, Baylor's chief operating officer, said that's standard in the hospital industry.

Across Texas, private sector workers this year paid $1,800 more in premiums per family policy, and $630 more per individual plan, to help pay for care of the uninsured, according to the Center for American Progress, a liberal-leaning Washington think tank, updating an earlier study by Democratic health care economist Kenneth Thorpe.

The Texas "cost shift" represents about 13 percent of all private premiums paid, far more than the national average of slightly more than 8 percent.

The average annual family policy premium, shared by employer and employee, is $13,500 in Texas, the center found. For individuals insured through jobs at private companies, the average is $4,800.

Rick Boss of Dallas risk management firm MHBT said insured employees aren't just paying higher premiums, but also higher deductibles and out-of-pocket expenses.

"Dallas employees certainly are picking up more than the national average," Boss said.

For an average family of four in Dallas, medical care and health insurance this year will cost nearly $17,000. Of that, 41 percent – almost $7,000 – will be paid by the employee, MHBT found in a survey of 139 local businesses.

In Dallas, average employee benefits are 7 percent leaner than nationwide, Boss said. Even after raising costs and cutting coverage, some businesses are at the breaking point, he said.

Between 1996 and 2006, the cost of family coverage for private sector workers in Texas increased 86 percent, while incomes increased by less than 9 percent, according to the Robert Wood Johnson Foundation, which finances health care research and supports universal health coverage.

Compared with the rest of the nation, the Texas economy relies heavily on small businesses and relatively low wages. So although most of the state's uninsured live in households with people who work, fewer employers offer coverage, and fewer employees can afford it.

Only 49.5 percent of the state's residents were covered by employer-sponsored insurance, in a two-year average ending in 2008, compared with 58.5 percent nationwide, the U.S. Census Bureau estimated this month.

The result is an even greater squeeze on public or taxpayer-funded hospitals. Parkland hospital and its affiliated neighborhood clinics carry most of the indigent-care load in Dallas County. Parkland levies $412 million in property taxes on county homeowners and businesses and receives about $175 million a year in special federal and state funds, which offset about $523 million a year in care for the uninsured and underpayments by Medicaid, officials said.

The Parkland system is in constant danger of coming up short, though, said president Ron Anderson and chief financial officer John Dragovits.

"It's basically a Rube Goldberg model of fragile financing," Dragovits said. "It's all of these bits and pieces that we've pulled together to make it all work. But any time something happens in Washington or Austin, it potentially puts us at risk."

Studies by the Institute of Medicine, a federal advisory panel, say the uninsured typically pay for about 35 percent of their care. The Parkland officials struggled not to laugh when asked if they collect that much.

"Today, if in America we could collect 35 percent of costs for the uninsured, we'd take that to the bank," said Anderson.

Parkland and its 11 community clinics serve many low-income residents. Half its patients are Hispanic, and 29 percent are black.

Researchers agree that illegal immigrants are a significant part of the uninsured population, both in Texas and nationwide.

Hospitals are required by federal law to treat everyone who comes into the emergency room, but most say they don't track how many are in the country without permission. Neither Parkland nor the Baylor Health Care System in Dallas asks incoming patients whether they are legal citizens.

Last year, Texas had 1.3 million to 1.55 million illegal immigrants, according to the Pew Hispanic Center, a nonpartisan research agency. The Census Bureau says that among the state's 6 million uninsured residents last year were 1.56 million noncitizens. Officials said they can't pinpoint how many of those are in the U.S. illegally.

Steven Camarota, research director at the Washington-based Center for Immigration Studies, a conservative group that supports stronger immigration enforcement, said that if immigrants and their U.S.-born children aren't counted, only New Mexico tops Texas in percentage of residents without health insurance – and by less than 1 percentage point.

"If I pull out the immigrants and their kids, Texas still ranks right near the top," he said.

The Center for Public Policy Priorities, an Austin group that supports Democratic proposals to overhaul health care now before Congress, reached a similar conclusion.

Joel Allison, chief executive of Baylor Health Care System, and other health care providers said a restrictive state Medicaid program helps swell the ranks of Texas' uninsured.

Though the federal government puts up most of the money for Medicaid, an insurance program for the poor, states set the rules. Texas rules bar coverage for an able-bodied adult who makes more than $188 a month and is not pregnant.

"Medicaid in Texas is very limited," Allison said.

State demographer Karl Eschbach, a professor at the University of Texas at San Antonio, said the state's low taxes and labor costs are attractive to business and helped make it "the last state, really" to enter the recession.

"But the tradeoff is, Texas industries that employ a large undocumented workforce here are not offering them health insurance options," he said. "People who don't like paying for uncompensated care should realize that one reason their housing costs are so low is that the construction industry isn't giving insurance benefits to its illegal immigrant workforce."

Beyond dollars, lack of insurance exacts a human toll. Nationally, 22,000 people died in 2006 because they lacked health insurance, according to the nonpartisan Urban Institute, a center-left economic and social policy research group. Along with the Institute of Medicine, the Urban Institute has cited studies showing that if uninsured women with breast cancer have their disease diagnosed later, treatment is less effective. Also, uninsured men with high blood pressure often skip seeing a doctor and fail to get medication, putting them at risk of serious harm.

Even the insured face risks from living with so many neighbors without insurance.

As hospital emergency rooms fill, many simply begin "diverting" patients elsewhere for a time. Increasingly, patients who've suffered a heart attack, stroke or car-wreck injuries are uninsured and can't pay.

That frustrates doctors who are specialists, and many no longer are willing to be on call for emergencies, said Emory University emergency medicine professor Arthur Kellermann. They can make more, be sued less and work better schedules performing elective surgery in private practice, he said.

"Everyone's access to care, particularly the most time-critical care, suffers," said Kellermann, who co-chaired an Institute of Medicine panel on the consequences of having so many uninsured Americans.

"Pressure on the system is going higher and higher and higher, the longer we put off dealing with this problem."

Staff writer Jim Landers in Washington contributed to this report.