The effort to create the first labor union at Amazon appeared headed for defeat, with votes against the move far outstripping those in favor when counting of ballots was paused late Thursday.
The tally stood at 1,100 votes of 'No' to the idea of forming a labor union in Alabama, versus 463 votes supporting the proposal when National Labor Relations Board officials halted for the evening.
Counting was to resume Friday morning.
About 55 percent of the more than 5,800 workers at an Amazon warehouse in the city of Bessemer cast ballots, according to the Retail, Wholesale and Department Store Union.
A simple majority will determine the outcome.
The RWDSU appeared to be girding for a loss, its president Stuart Appelbaum putting out a statement accusing Amazon of taking advantage "of a broken system."
"We will be calling on the labor board to hold Amazon accountable for its illegal and egregious behavior during the campaign," Appelbaum said.
Counting that was due to begin last week was delayed due to questions regarding whether all of the 3,215 ballots were eligible to be included in the tally.
The labor board is overseeing the count, which comes at the end of a contentious unionization campaign which has drawn national attention and the involvement of numerous political figures and activists.
A bruising months-long battle has sparked intense debate over workplace conditions at Amazon, which has more than 800,000 US employees.
Unions and political leaders have argued that Amazon employees face constant pressure and monitoring, with little job protection, highlighting the need for collective bargaining.
Amazon has argued that most of its workers don't want or need a union and that it already provides more than most other employers, with a minimum $15 hourly wage and other benefits.