Labor union leadership and members are finding themselves in the middle of an increasingly heated debate over the rights of undocumented workers in the Washington area.

Some labor unions such as the Service Employees International Union’s Local 32BJ, which represents more than 85,000 property service workers from stadium workers doormen, are working with immigrant-advocacy groups such as CASA of Maryland and the National Capital Immigration Coalition. Spokeswoman Kate Ferranti said local 32BJ members helped the groups to organize lobby days for federal immigration reform and are working with those same organizations to plan out responses to Prince William and Loudoun counties’ efforts to discourage illegal immigrants from living inside their borders.