USA Today raised eyebrows in June with an expose’ alleging labor abuses at trucking fleets operating at the Southern California ports. Now the newspaper is reporting that in the wake of that story, Costco will no longer do business with one of the fleets highlighted in the story.

The newspaper reported that some port drivers were working long hours and taking home very little – in some cases none – of their paychecks after their lease payments and other expenses were deducted. The report claimed that in some cases drivers were being forced to work as much as 20 hours in a day, far past the maximum allowed by law, drivers alleging that their supervisors threatened to take their jobs or assigning lower-paying routes as punishment if they did not.

Now Costco, one of the largest U.S. retailers, has announced it will no longer do business with Pacific 9 Transportation.

Pacific 9 told USA Today that it had stopped leasing trucks to drivers before Costco ended its relationship, and the company had launched reforms to improve pay.

In the wake of the June report, the Harbor Trucking Association, which represents fleets at the ports, told HDT the cases reported by USA Today were cherry-picked for their extremeness or were not completely explained. "It focuses on a very small subset of the industry, and what we forget to point out is the 90-plus percent of drivers who prefer to be independent contractors and have made that business model work."

Costco's action comes on the heels of additional fallout from the story, USA Today reports, including four senators, led by Senator Sherrod Brown (D-OH), sending letters to 16 U.S. retailers urging them to take a stand against “shameful” labor abuses.

In the wake of these actions, the paper reports, Hewlett-Packard also sent an auditor to investigate the company’s labor practices, while Walmart pledged in a letter responding to the senators that it would cancel contracts with any trucking company that did not provide “assurances” it was following fair labor practices.

In the letter, Walmart Executive Vice President Joy Jorgensen wrote that, “The stories profiled in that article are deeply concerning. Any motor carrier that fails to comply with law, such as those alleged in the article, would be in violation of our contract and would therefore be subject to cancellation.”

According to USA Today in the wake of its reporting, “a wave of pressure from retailers and manufacturers has hit port trucking operations across the industry, according to drivers who say their employers have been fielding calls from clients."