• Last December, a tornado tore through an Amazon warehouse in Illinois, killing six workers.

• In March, House members launched an investigation into Amazon's severe weather safety practices.

• But, they said, Amazon failed to comply and accused the company of "obstructing" the investigation.

Congressional Democrats have slammed Amazon, saying the company has made it difficult to investigate whether its labor practices resulted in workers' deaths after a tornado struck one of its Illinois warehouses last December.

In March, in response to the incident, House Oversight Committee members Carolyn Maloney and Alexandria Ocasio-Cortez of New York and Cori Bush of Missouri reached out to Amazon CEO Andy Jassy for information on Amazon's severe weather policies. They gave Jassy and Amazon an April 14 deadline to hand over documentation.

But weeks after the deadline, the group said they still hadn't received any documentation from Amazon. In a letter dated June 1, the Maloney, Ocasio-Cortez, and Bush reached out to Jassy again, noting that "nearly seven weeks have passed since the April 2022 deadline, yet Amazon still has not produced any of the key categories of documents identified by Committee staff."

Amazon "has failed to meaningfully comply with the Committee's requests, obstructing the Committee's investigation," the group wrote.

Amazon now has until June 8 to submit the documents. "If Amazon fails to do so, the Committee will have no choice but to consider alternative measures to obtain full compliance," the letter said.

Amazon spokesperson Kelly Nantel told Bloomberg on Friday that the company was surprised by the letter because it had provided more than 1,500 pages of documents to assist in the investigation.

"As we have done from the start, we will continue to work with committee staff on further document production — which includes the most recent materials we shared on June 1," Nantel said.

Amazon did not immediately respond to Insider's request for comment.