Just a week before a Teamsters contract for more than 325,000 United Parcel Service workers is due to expire on Aug. 1, the UPS still hasn’t resolved disputes over pay for part-time workers.
If the walkout happens, it could rattle the U.S. economy.
Union and company negotiators have yet to reach an agreement.
The strike could knock the American economy off stride since UPS handles about one-quarter of the tens of millions of packages that are shipped daily in the United States.