Hundreds of Amazon workers are speaking out against their employer’s record on climate change, risking being fired to defy a company-wide ban against such public criticism.

The group Amazon Employees for Climate Justice published comments from 357 workers on Sunday, many of which highlight what workers see as Amazon’s hypocrisy. The company has pledged to use only renewable energy sources in the future and cut its carbon emissions, but it continues to work with and improve the businesses of oil and gas companies.

“It is unconscionable for Amazon to continue helping the oil and gas industry ... while trying to silence employees.”

“The science on climate change is clear,” writes Amelia Graham-McCann, a senior business analyst at the company. “It is unconscionable for Amazon to continue helping the oil and gas industry extract fossil fuels while trying to silence employees who speak out.”

According to a recent report from The Guardian, just 20 companies are responsible for one-third of all greenhouse gas emissions since 1965, and a number of these (including BP and Shell) rely on Amazon for cloud computing, machine learning, and data services.

“I want Amazon to continue its vision to be Earth’s most customer-centric company,” writes Melissa Reeder, a senior UX designer. “By ending our contracts with oil and gas companies, we can show the world we put people over profits and be a leader against climate change.”

This sort of public criticism is forbidden by Amazon’s communications policy. A spokesperson for the company told The Verge that employees are instead encouraged to join internal groups and submit questions at company Q&As.

“While all employees are welcome to engage constructively with any of the many teams inside Amazon that work on sustainability and other topics, we do enforce our external communications policy and will not allow employees to publicly disparage or misrepresent the company or the hard work of their colleagues who are developing solutions to these hard problems,” said the spokesperson.

By criticizing Amazon in public, employees risk being fired — a threat received by workers who spoke out on the issue earlier this month. But those involved in this mass action hope that by coordinating their criticism, they’ll avoid such punishment. According to a report from Recode, an email sent out by the Amazon Employees for Climate Justice soliciting comments from workers reassured peers that there is “strength in numbers.”

The latest example of Silicon Valley workers organizing from the ground up

The action is the latest example of Silicon Valley workers organizing in an attempt to shift employers’ policies. Protests over the last few years have included a Google walkout in response to the company shielding men accused of sexually harassing colleagues and Microsoft employees protesting both “complicity in the climate crisis” and work with ICE.

Although the number of Amazon employees who published comments today is small compared to the firm’s total workforce (roughly 750,000, including warehouse staff), they represent a range of high-skilled jobs, such as data scientists and software developers.

The published comments are far from uniformly critical. Many praise Amazon for its current commitments to tackling climate change but say that if the company is true to its culture of bold leadership, it needs to do more — and let employees speak out.

“I love working at Amazon,” writes Mark Hiew, a senior marketing manager. “One of the things I like most is our leadership principle to ‘Have backbone, disagree and commit.’ In this moment in our country’s political and corporate history, I think it’s more important than ever for employees to have freedom of speech to speak publicly about their employer’s actions.”

Amazon did not answer The Verge’s questions as to whether these individuals would be punished for publishing their comments.

Update January 27, 12:30PM ET: Added a video from Amazon Employees for Climate Justice.