Strike vote underway for 340,000 UPS workers

COLUMBIA, S.C. (CNN)– The clock is ticking on what could be a major strike that has the potential to affect millions of American households.

Workers with United Parcel Service will vote this week to authorize a strike if their union does not reach a new contract by August 1. The vote results will be announced June 16.

Now – if employees walk, it would be the largest work stoppage in U.S. history.

UPS has 340,000 employees. While its union, the International Brotherhood of Teamsters represents more than half the work force.

UPS and the Teamsters began negotiations last April. The company says it has reached an agreement on several major issues.

Both sides are bargaining over pay increases, benefits and better working conditions.