A group of 84 workers at Amazon's warehouse in Palmdale, California, won voluntary recognition by Battle-Tested Strategies, a third-party delivery contractor, to be represented by the Teamsters.

Battle-Tested Strategies is one of the legions of third-party delivery firms contracted by Amazon to shuttle packages to shoppers' doorsteps.

"We want fair pay and safe jobs, to be able to provide food for our families," said Rajpal Singh, an Amazon delivery driver at the Palmdale facility, in a statement. "We want to know we will make it home to our families at night after delivering Amazon packages in the extreme heat. We organized with the Teamsters to change our working conditions for the better."

Amazon said in a statement that it had terminated Battle-Tested before Monday's union announcement, though it didn't say when the contract ended.