A small group of equipment maintenance and repair technicians at Amazon’s Middletown, Del., warehouse rejected union representation Wednesday night by a wide margin.

If it had been approved, it would have been the first bargaining unit for Amazon in the U.S.

The workers voted 21-to-6 against having the International Association of Machinists and Aerospace Workers represent them and seek a contract with the online retail giant. The Machinists represent tens of thousands of Boeing employees in Seattle and elsewhere.

“With today’s vote against third-party representation, our employees have made it clear that they prefer a direct connection with Amazon,” company spokeswoman Mary Osako said in a statement. “This direct connection is the most effective way to understand and respond to the wants and needs of our employees.”

The vote comes a month after workers at the warehouse, a tiny fraction of the 1,500 employees at the Delaware facility, filed a petition with the National Labor Relations Board to hold elections to form a bargaining unit. To hold the election, the Machinists needed support from at least 30 percent of the 30 workers that it sought to represent in contract negotiations with Amazon. The union clearly lost some support in the intervening month.

Machinists spokesman John Carr said Amazon’s campaign to discourage unionization with meetings at the warehouse worked. “The pressure that these workers faced was intense and was more than they could overcome,” Carr said.

Workers initially sought union representation over grievances about arbitrary job classifications, promotion and vacation policies. Carr said the Machinists will continue to try to persuade warehouse workers to support the union. But labor laws require a one-year wait before holding another vote on representation.

Amazon has steadfastly opposed unionization efforts. The company is also fighting union organizers at three warehouses in Germany. There, more than 1,000 members of German’s Ver.di union, who don’t have a contract, walked off the job last month to protest their pay. Last week, some of Amazon’s German workers put together a petition to oppose the unionization efforts of their colleagues.

Jay Greene: 206-464-2231 or jgreene@seattletimes.com. Twitter: iamjaygreene