Today [June 28], the International Brotherhood of Teamsters walked away from the national bargaining table and officially demanded UPS exchange its last, best, and final offer no later than June 30.

The Teamsters gave UPS a one-week notice on Tuesday to act responsibly and exchange a stronger economic proposal for more than 340,000 full- and part-time workers. UPS executives couldn’t make it one more day without insulting and ignoring union leaders and rank-and-filers as negotiations resumed on Wednesday.

“The largest single-employer strike in American history now appears inevitable,” said Teamsters General President Sean M. O’Brien.

With a deadline of Friday to return a last, best, and final offer, UPS risks putting itself on strike by August 1 and causing devastating disruptions to the supply chain in the U.S. and other parts of the world. Teamsters nationwide overwhelmingly authorized a strike this month by 97 percent should UPS fail to come to terms on a new contract. UPS’s impending failure is one step closer to reality and has the potential to affect nearly all Americans.