Some staff at Amazon’s warehouse in New Jersey, where a worker died earlier this month during the Prime Day rush, are furious with the e-commerce giant’s response – and are demanding that more information is published.

Two workers at Amazon’s EWR9 factory in Carteret, NJ spoke out anonymously to NBC Newsclaiming that the man died on an upper floor known for its high temperature.

One said his deceased colleague had worked as a “water spider”, a job that involved transporting goods around the facility.

The other said she asked her superiors about his death but was given no information – and was told not to talk about it. She added that frustration at the warehouse was high.

“It’s scary,” she said. “We should know what happened and how it happened. It could have been any of us.

The death of the as yet unidentified worker occurred on July 13 during Amazon’s Prime Day sale, which is traditionally one of the busiest weeks of the year for the online retailer. He launched an investigation by the Occupational Safety and Health Administration.

Amazon union president Chris Smalls, who rallied a corporate warehouse in Staten Island to a union victory earlier this year, tweeted Thursday that the worker had been “unconscious on the ground for more than 20 minutes” and that it had been “nearly an hour” before 911 was called. He also said the man told management he was experiencing chest pains but they refused to let him take a break despite the “hot conditions”.

Smalls, who did not return messages, called the incident “disturbing” and also tweeted that he will file “a complaint with local OSHA” and that his union will “organize EWR9”.

Amazon’s spokesperson told NBC News in a statement that the death “was related to a personal medical condition.”

The company is investigating the incident, but has not yet released its findings.