In advance of a crucial City Council committee hearing, business and labor leaders Friday haggled over details of an ordinance guaranteeing many workers advance notice of their schedules.

With support from Mayor Lori Lightfoot and progressive aldermen, the Fair Workweek Ordinance has gained momentum. Business groups who once opposed the new government mandate have switched tactics and are now arguing instead for changes in its terms.

“We have met the proponents’ goal of advance notice. This will be the most expansive scheduling ordinance in the country. Now, we just need a little balance in the language,” said Jack Lavin, president and CEO of the Chicagoland Chamber of Commerce.

Robert Reiter, president of the Chicago Federation of Labor and a principal advocate or the ordinance, said any changes would be relatively minor. He said he expects the City Council’s Committee on Workforce Development will pass the ordinance Monday, sending it to the full council.

Mayor Lori Lightfoot’s staff, Reiter said, is deeply involved in the discussions, trying to make sure the ordinance has no unintended consequences. “They’re all trying to be thoughtful about this and make sure they are making good public policy,” Reiter said. The CFL has an ownership stake in Sun-Times Media.

A working draft of the ordinance provided Friday to the Sun-Times would require a 10-day advance notice of work schedules starting April 1, 2020. Two years later, the minimum notice would go to 14 days.

In that working draft, the ordinance would apply to businesses with 100 or more full- or part-time employees. Prior versions had the cutoff at 50 workers. Within those businesses, the ordinance would cover all hourly workers and salaried employees earning less than $50,000 a year.

In addition, the draft includes a huge exemption for the restaurant industry; the ordinance would apply only to restaurants with more than 30 locations globally and at least 250 employees.

Michael Jacobson, president and CEO of the Illinois Hotel & Lodging Association, said the ordinance has been pitched as helping low-wage workers, but in reality would end up covering a broader group. He said it should cover only the hourly staff that make up to $25 an hour, including tips.

Another dispute is whether employers can establish a voluntary standby list for people who want extra work on short notice.

Reiter said companies could demand an employee join the list as a condition of hiring or advancement. Lavin said such a list is part of a law in Oregon and there have been no reported abuses.

“Our overall goal is not to defeat this,” Jacobson said. “It’s to reach an agreement that’s best for everybody.” He praised the mayor and aldermen for considering alternative points of view.

“My members are not bad employers. I fully support putting maximum penalties in place for any violations,” Jacobson said.

Lightfoot has said she supports the ordinance and that the issue of predictable schedules is personal to her. In an op-ed in the Sun-Times, Lightfoot wrote about her mother, who was a nurse’s aide, and her difficulties arranging child care when she didn’t know her shifts from week to week.

Reiter said an earlier business campaign assailing the ordinance, saying it would prevent hospitals from responding to emergencies, was off base. The ordinance’s draft contains several exemptions to the advance notice rule, such as for power outages, “acts of nature,” civil unrest or other unexpected events.

But Lavin insisted many employees prefer flexibility.

“We’re trying to negotiate the best we can to help companies implement this,” he said. “It will make scheduling more rigid, which workers will not like.”