Teamsters members and the United Parcel Service could be heading toward the nation’s largest strike in decades.
The union announced Tuesday that members voted 93% in favor of going on strike, if a deal is not reached before the current labor contract expires on August 1.
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Denis Taylor, a Teamsters director and co-chairman of the bargaining committee said in a statement to CBS Money the members' vote "gives the negotiating committees bargaining leverage this week and during subsequent negotiations for the national contract and the supplements.”
UPS employs 260,000 Teamsters, and added 40,000 members since its current contract was reached five years ago.
The shipments UPS transports equal an estimated 6% of the nation's Gross Domestic Product (GDP), which means a labor dispute could disrupt the US economy, CNN Money reports.
A strike could cause the shipping giant major problems in offering deliveries seven days a week.
Last year, UPS began offering Saturday deliveries and hasn’t officially announced plans for Sunday, but according to the union, several proposals to expand weekend deliveries have been made.
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One proposal on the table is to create a two-tier wage system that would take part-time workers earning $15 an hour to full-time at the same wage. Existing full-time drivers earn an average of $36 an hour, or about $75,000 a year.
Union members are split on the proposal, making it harder to reach a deal and avoid a strike.
Members of the UPS Teamsters United say the delivery giant, which recorded $5 billion in profit last year, should pay new full-time employees the same as existing employees.
The last strike by UPS workers in 1997 lasted 16 days, with only 180,000 Teamsters at the company at that time. At double the number, this strike could last much longer.