“That happened to me, but also, not just to me,” Rojas, 45, said through an interpreter. “This is probably happening to lots of workers.”

Forty percent of Maryland’s private-sector workers — nearly 820,000 people — have no option to take time off with pay if they’re ill, according to estimates from the Institute for Women’s Policy Research.

Now three Baltimore groups that advocate for workers are launching a campaign to require paid leave in the state, calling it a public-health issue as well as a matter of basic fairness. Business groups, however, argue that adding regulatory mandates can stall job growth .

Nationwide, there’s a have-and-have-not aspect to paid leave. Most high-wage workers have it; most low-wage workers don’t.

“All of us at some time do get sick, our kids get sick, our parents get sick,” said Jason Perkins-Cohen, executive director of the Job Opportunities Task Force, one of the organizations behind the new Working Matters coalition. “If you aren’t able to accrue leave … what are you supposed to do?”

Paid leave is guaranteed in much of the world but only in a few places in the United States: Connecticut, San Francisco, Seattle and the District of Columbia. Activists are also pressing for laws in several other cities, including New York, and more than a dozen states.

Local business groups aren’t eager for Maryland to join in . They say that requiring paid leave would burden companies that don’t have a lot of workers — or a human-resources department to manage leave.

“I think it’s crossing dangerous territory when a government steps in and mandates these kinds of benefits for workers, especially for very small businesses ,” said Kathleen T. Snyder, president of the Maryland Chamber of Commerce. “We need to be careful about these well-meaning mandates, which may not have the effect that we want, which is to create more jobs for Marylanders.”

The National Restaurant Association and its state affiliates have been among the most active opponents of paid-leave laws. Three-quarters of food preparers and servers aren’t eligible for sick leave.

The Maryland proposal is still in the formative stage, and the Restaurant Association of Maryland said it couldn’t comment on it until there’s a specific proposal. Generally, though, the trade group is concerned about “one size fits all” requirements, said Melvin R. Thompson, senior vice president of government affairs and public policy at the association.

The few U.S. jurisdictions with sick-leave laws have set a lower requirement, or no requirement, for small employers. In Seattle, for instance, workers accrue a maximum of five to nine days a year, depending on the size of the employer, but businesses with fewer than five employees are exempted.

San Francisco’s law, which also ranges from five to nine days but covers all employers, is the longest-standing in the country at six years old. Two-thirds of that city’s employers said they support the law, and more said it had no negative effect on their profitability, according to a 2009 survey of 727 small and large businesses by the Institute for Women’s Policy Research.

“We believe that paid sick leave is good public policy,” said Donna Levitt, manager of San Francisco’s Office of Labor Standards Enforcement.

The average cost for private-sector employers offering sick leave in the U.S. is 23 cents an hour per employee, according to the Bureau of Labor Statistics. That’s about the experience of San Francisco restaurateurs, but it’s hard to parse out the full impact because the city also increased the minimum wage and required employers to provide health care in recent years, said Rob Black, executive director of the Golden Gate Restaurant Association.

“You do want to make sure you’ve got people who aren’t coming to work sick, but there’s a real cost to it,” Black said of paid leave. “It’s a complicated issue.”

Advocates contend that workers without paid leave are ultimately more expensive for their employers, and the community, because they spread illness or make mistakes.

Workers with paid leave are less likely than those without it to delay medical treatment for themselves or their family, or to end up at the emergency room, according to an Institute for Women’s Policy Research analysis of Centers for Disease Control and Prevention data last year.

Workers with paid leave are also 28 percent less likely to get hurt on the job than those without, according to a study this summer by the National Institute for Occupational Safety and Health.