In recent years, organized labor has taken advantage of a new tool to represent and advocate for employees: the micro-union. The term describes unions that represent subcategories of employees within a given company—for example, at a cafe, there might be one micro-union to represent waiters and waitresses, another micro-union to represent cooks, another for busboys, and so on—and the spread of micro-unions has serious implications for both employers and workers across the country.

Micro-unions have flourished thanks to the National Labor Relations Board’s (NLRB) ruling on the Specialty Healthcare Rehabilitation Center of Mobile case in 2011. An affiliate of the United Steelworkers proposed the unionization of only certified nursing assistants (CNAs) at a nursing home in Mobile, Alabama, but the employer disagreed, arguing that all employees—not just the CNAs—could be effectively represented by one union. The NLRB’s previous case standard for micro-unions, 1991’s Park Manor Care Center, supported the employer’s position, as it asserted unions must include all employees who constitute a “community of interest.”

However, the NLRB rejected the previous standard in their final ruling on Specialty Healthcare and instead issued new guidelines on micro-unions. Now, union petitions would not be rejected “simply because it is small,” paving the way for micro-unions to form in all industries, where they could represent subsets of employees based on their job duties in ever-smaller bargaining units. It also opens the door for unions to form even when a majority of employees at an organization do not support unionization: When union organizers can’t win an election outright, they can just find a group or department that supports unionization and use them to carve out a foothold in that company or industry.

While employees may have an easier time securing representation thanks to micro-unions, for employers, the Specialty Healthcare ruling has prompted concerns over collective bargaining agreements. Now, since bargaining units can form to represent individual departments within larger organizations, employers may find themselves in the position where they must negotiate separate agreements with each micro-union.

This could be problematic for organizations like grocery stores, which may have to negotiate with separate unions for cashiers, janitors, bakers, butchers, etc., in addition to department stores, malls, hospitals, and others. To avoid this dilemma, experts have suggested merging employees’ duties so they all share the same responsibilities—everyone answers the phones, mops, and stocks shelves equally—in order to prevent new, smaller “communities of interest” from petitioning for union representation and forming micro-unions.