Sean O’Brien, the union’s president, said in a statement late Wednesday that “if your package is delayed during the holidays, you can blame Amazon’s insatiable greed.” The Teamsters had given Amazon until December 15 to agree to contract talks.

“We gave Amazon a clear deadline to come to the table and do right by our members. They ignored it,” said O’Brien. “These greedy executives had every chance to show decency and respect for the people who make their obscene profits possible. Instead, they’ve pushed workers to the limit and now they’re paying the price. This strike is on them.”