Los Angeles County has more uninsured people than anyplace else in the country – three million, many of them immigrants, and many of those undocumented. If the Senate version of health bill passes, with its ban on federal coverage of non-citizens, a million people in California will be denied health insurance–the great majority of them in L.A.

That would be a disaster for Los Angeles.

The Senate bill, like the House version, would create insurance exchanges and give federal subsidies to low-income people to buy their own coverage. The Senate bill, however, would prohibit those who are not U.S. citizens from participating in the exchanges. The House bill is slightly better — it allows legal immigrants who aren’t citizens to buy insurance through the exchange, although it denies them federal subsidies.

Both Senate and House bills will hurt Los Angeles, as Tim Rutten pointed out in the L.A. Times: “Neither version makes any provision for undocumented immigrants.”

LA is not the only city with substantial numbers of immigrants and undocumented residents. New York City must come in second. Rutten cities a report by the Congressional Budget Office showing that the Senate bill leaves 23 million American residents without health insurance, and 7 million of those people are undocumented. The House version leaves 18 million people without coverage, and 6 million of those are undocumented.

The three million L.A. residents who lack health insurance now get their medical care mostly from emergency rooms at county hospitals. Those hospitals have an ethical and practical obligation to provide health care to the ill and injured even if they aren’t insured. The federal government currently subsidizes their care at hospitals with “disproportionate” numbers of such patients, including those in L.A.. The House bill, Rutten reports, reduces those federal payments only modestly, but the Senate bill requires deep cuts.

That means L.A. county will pay for a lot more of the medical expenses of undocumented residents. And L.A. county doesn’t have a lot more money to pay for anything right now.

The underlying issue here is immigration reform – California more than most states needs a path to legalization for undocumented people. But until that happens, it’s vital that the health care bill Obama signs not penalize L.A. and other counties for providing emergency room care for its residents who are not citizens.