The APWU represents clerk, maintenance, and motor vehicles craft employees at 21 Bulk Mail Centers in metropolitan areas around the country.

The BMCs are unique: They were established in 1974 to process large parcels, and the mechanized equipment required to sort the oversized packages created working conditions unlike those at other postal facilities.

BMC employees faced other unusual circumstances as well: The parcel sorting operations were moved from other facilities, so a large percentage of the original BMC employees were involuntarily transferred, or excessed, into their assignments.

When the BMCs were established, union members were faced with a choice regarding representation: they had to decide whether to become part of established APWU locals or create new ones. Members at half the BMCs petitioned the union's National Executive Board for authority to create their own locals, while workers at the remaining BMCs became part of existing locals.

In 1980, BMC locals submitted a resolution to the APWU National Convention, seeking to establish regular meetings to address the unusual problems faced by their members. The resolution was adopted unanimously. Bulk Mail Center representatives meet each year to discuss issues of special concern to BMC employees.