The U.S. National Labor Relations Board said Monday that employees at an Amazon warehouse in New York’s Staten Island district have filed a petition to unionize.

Amazon, however, questioned the move and expressed doubts about whether enough legitimate signatures had been collected.

The workers’ move is the second time this year that employees of the world’s largest online retailer have expressed a desire to unionize this year, following a failed attempt at a warehouse in Alabama in April. Although the online retail giant has long fought against unionization, many workers are demanding more protection and benefits in the face of the ongoing COVID-19 pandemic, which has threatened their safety.

Chris Smalls, a former Staten Island warehouse worker, led the campaign and collected about 2,000 signatures to make way for an official vote on the NLRB. Smalls rose to prominence last year when Amazon fired him for allegedly breaking paid pandemic-related quarantine when he went to his factory to protest working conditions.

The organizing drive is being held at Amazon’s only fulfillment centre in New York City, one of the retail giant’s large warehouses from which many products are shipped.

“This is monumental for the workers.”This is proof that you can stand up, fight back and organize your workplace, ” Smalls said in an interview.