The city would offer health care to any adult resident, regardless of immigration or employment status, under a plan announced Tuesday.

The plan, which still needs be approved by the city's Board of Supervisors, is aimed at 82,000 uninsured residents who earn too much to qualify for Medicaid, said Mayor Gavin Newsom. San Francisco already provides universal health care for children.

''Rather than lamenting about the fact that we live in a country with 45.8 million Americans that don't have health insurance ... San Francisco is doing something about it,'' Newsom said. ''San Francisco is moving forward to fulfill its moral obligation.''

Newsom stressed that the so-called Health Access Plan was not meant to take the place of private health insurance, but rather provide a way to consistently treat people without insurance so they don't end up seeking medical care in hospital emergency rooms.

Unlike health insurance, for example, the city's plan would not cover the cost of any medical services its participants seek outside San Francisco, and it would not be open to people who work, but do not live, in the city.

It would provide comprehensive preventive and catastrophic health care, covering everything from checkups, prescription drugs and X-rays to ambulance rides, blood tests and surgeries.

The city estimates the plan would cost $200 million a year, an expense that would be borne by taxpayers, businesses that don't already insure all their workers, and participants themselves.

Residents would pay both monthly fees and service co-payments on a sliding scale depending on income. A person with annual earnings at the federal poverty line would pay $3 per month, while someone who makes between $19,600 and $40,000 -- or up to 400 percent above the poverty line -- would pay an average of $35 per month.

Details of how the employer contribution would work were scheduled to be presented Wednesday to the Board of Supervisors. Approval is expected, though the details could change.

The most recent version, sponsored by Supervisor Tom Ammiano, would require every business with more than 20 employees to pay $1.60 an hour into the system for all employees not already covered by a health plan, no matter how few hours they work.

Laurie Thomas, owner of three restaurants in San Francisco, said that she already contributes to health insurance for her employees who work more than 28 hours a week, but that the hourly mandate Ammiano is proposing would put her out of business.