Senator Bernie Sanders and Amazon are locked in a war of words over alleged unsafe conditions and low pay in Amazon's warehouses.

In a response to Amazon's blog post criticizing the senator, Sanders said it would call on the Occupational Safety and Health Administration to investigate Amazon's warehouses for "unsafe working conditions."

Sanders noted incidents at Amazon warehouses in over the years, including seven Amazon workers who died on the job since 2013, according to the National Council for Occupational Safety and Health.

Bernie Sanders just escalated his war of words with Amazon.

The senator, in a response to an Amazon blog post critical of Sanders' criticisms of the company, said he would call on the Occupational Safety and Health Administration to investigate "unsafe working conditions" in the company's warehouses.

"It’s not only low wages that are of concern with regard to Amazon," Sanders' statement reads. "There are deeply disturbing stories about working conditions at fulfillment centers run by Amazon and its contractors."

Sanders cites a report from the National Council for Occupational Safety and Health that came out in April that found seven Amazon warehouse workers who died on the job in Amazon's warehouses since 2013. Three of the workers died within five weeks of each other in 2017.

Amazon was one of the "dirty dozen'" on a list composed by the NCOSH, a private nonprofit worker advocacy group. Amazon landed on the list for "a disturbing pattern of preventable deaths," the report says,

In a statement to Business Insider in April, Amazon defended its workplace safety record, noting the training all employees have to go through, and its commitment to improving safety throughout its warehouse network in conjunction with its high standards.

Amazon also said that it takes "any serious incident" seriously, and is working to improve.

"While any serious incident is one too many, we learn and improve our programs working to prevent future incidents," the statement read. "We are proud of safety record and thousands of Amazonians work hard every day innovating ways to make it even better."

Sanders statement was in response to a blog post published by Amazon on Wednesday defending its reputation over Sanders' repeated criticisms of the company, including pay low enough where workers require food stamps, and unsafe conditions in Amazon warehouses.

Amazon did not immediately respond to a request for additional comment.