[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/09/22/art.maxchuck0922.gi.jpg caption="Republican Sen. Charles Grassley, right, asked the CBO to analyze a proposal by Democratic Sen. Max Baucus, left, as well as health care reform legislation drafted in the House of Representatives."]
WASHINGTON (CNN) - The number of unauthorized immigrants who might illegally access health care subsidies under currently debated health care bills is too uncertain to calculate, the Congressional Budget Office said Tuesday.
The independent, nonpartisan legislative office estimated earlier this month that the bill proposed by Senate Finance Chairman Max Baucus, D-Montana, would cost $774 billion.
In a letter Tuesday to Sen. Chuck Grassley, R-Iowa, the budget office said its cost calculation included those who may try to cheat the system by misreporting income or family circumstance as well as access by unauthorized immigrants.
However, "we have no basis for quantifying those factors separately for this or other proposals," the letter said.
Grassley had asked the agency for details about health care coverage for illegal immigrants under both Baucus' proposal and the House's health care proposal.
Under the Baucus plan, unauthorized immigrants would not be eligible for coverage through what is called the "exchange," where consumers could choose among insurance plans or a government-run plan, the Budget Office said. They also would be ineligible for government subsidies. The verification process would be similar to the process that currently exists for Medicaid.
Stringent enforcement of a verification process would keep more illegal immigrants from getting insurance or subsidies from the government, but could discourage some eligible individuals from applying, the letter said.
In addition, vigorous enforcement would reduce subsidy costs to the government, but increase administrative costs, it said.
The House bill also would deny government subsidies to unauthorized immigrants. But according to a report by another independent government agency, the Congressional Research Service, the language of the bill does not set restrictions to the insurance exchange based on immigration status.
The Budget Office's letter to Grassley states that it took noncompliance with the law into account, "but again, we cannot provide a specific figure for coverage of unauthorized immigrants under that proposal."
The office did, however, provide estimates for how many immigrants living in the country illegally are insured under current law.
The agency projected that by 2019, there will be some 14 million unauthorized immigrants living in the United States. Of those, nearly 60 percent, or 8 million, will be uninsured, the letter said. About 4 million will be insured through employment-based coverage, and another 1 million will have some alternate form of insurance, not including Medicaid, the Budget Office said.
The remaining 10 percent, or about 1 million unauthorized immigrants, will be covered through some form of Medicaid, it said. This coverage is possible under the current law, which allows illegal immigrants some Medicaid coverage for emergency care if they would be eligible for the program outside of their immigration status, the letter said.
The estimate of illegal immigrants on Medicaid includes those who access the benefits fraudulently, but "we believe that state agencies administering the Medicaid program successfully screen out most ineligible individuals," the letter said.