New worker-friendly sick leave requirements that become law in San Francisco on Feb. 5 have some employers’ lawyers scratching their heads.

The ordinance, which passed by a wide margin in the November election, requires San Francisco employers to dole out paid sick time benefits to all of their workers who are “employed within the geographic boundaries of the city.” Among other provisions, it will require that employees accrue one hour of paid sick time for every 30 hours worked, up to certain limits.