“The company’s quest for profits at all costs has led to unsafe physical environments, intense pressure to work at unsustainable rates and inadequate medical attention for tens of thousands of Amazon workers every year,” Sanders said in the nearly 10-page letter.

Sanders blamed Amazon’s executives and their “immense wealth” for decisions that force employees to work in these “unsafe environments,” resulting in a turnover rate as high as 150% per year.

“Amazon is one of the most valuable companies in the world worth $1.3 trillion and its founder, Jeff Bezos, is one of the richest men in the world worth nearly $150 billion,” Sanders wrote, adding that with all of its wealth “Amazon should be one of the safest places in America to work, not one of the most dangerous.”

“In its endless pursuit of profits, Amazon sacrifices workers’ bodies under the constant pressure of a surveillance system that enforces impossible rates,” Sanders wrote. “When faced with worker injuries, Amazon provides minimal medical care … This system forces workers to endure immeasurable long-term pain and disabilities while Amazon makes incredible profits from their labor.”

The Occupational Safety and Health Administration has cited Amazon for safety violations, including earlier this year when three of its warehouses failed to keep workers safe.

“Each of these inspections found work processes that were designed for speed but not safety, and they resulted in serious worker injuries,” Doug Park, assistant secretary for OSHA, said in a statement in January.

“While Amazon has developed impressive systems to make sure its customers’ orders are shipped efficiently and quickly, the company has failed to show the same level of commitment to protecting the safety and well-being of its workers.”

Safety violations were reported at three more Amazon warehouses a month later.

According to Sanders, Amazon’s serious injury rate is double the warehousing industry’s average.

“For tens of thousands of workers, the cost of just a few years at an Amazon warehouse is a lifetime of pain,” Sanders told Jassy.

As part of the Senate committee’s investigation, Sanders demanded that Amazon provide information about the high injury and turnover rates at the company’s warehouses. The senator also created a webpage to allow Amazon workers to submit their stories anonymously.

“Chairman Sanders wants to hear from current or former workers, supervisors, medical staff or anyone else in Amazon’s warehouses about their experiences to help inform that investigation,” the webpage said.

“Most Americans understand we live in a rigged economy,” Sanders said on the Senate floor Tuesday.

“Tomorrow, the HELP Committee begins the difficult and long journey of beginning to bring justice to the working class of this country and tell the CEOs, and the corporate executives and the 1%, that they cannot have it all.”