The City of San Francisco is taking steps to provide health care to all  of its 82,000 uninsured residents, paid for by a combination of public money and assessments on employers that do not provide health care for their employees:
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...
The most recent version [of the legislation], 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.
A version of this "pay or play" or "fair share" approach to providing health care was narrowly defeated in a statewide initiative in 2004, but San Francisco voters supported the idea by 70%. So it's natural for the city to implement a version locally.
For more on the Fair Share model, see Progressive States' LegAlert  on the topic.