US labour officials have found that Amazon “illegally retaliated” against two former employees who were fired after speaking out about the firm’s environmental practices and warehouse safety.

The National Labor Relations Board (NLRB) has ruled in favour of former Amazon employees Emily Cunningham and Maren Costa, who helped organise the group Amazon Employees for Climate Justice and were fired last April.

Amazon said that it disagreed with the ruling.

An Amazon spokesperson said: “We support every employee’s right to criticise their employer’s working conditions but that does not come with blanket immunity against our internal policies, all of which are lawful.

“We terminated these employees not for talking publicly about working conditions, safety or sustainability, but rather, for repeatedly violating internal policies.”

The NLRB, which saw the number of complaints filed against Amazon triple in 2020, according to NBC News, said it will file its own complaint against the business if it does not settle the case brought by Cunningham and Costa.

Cunningham told The New York Times: “It’s a moral victory and really shows that we are on the right side of history and the right side of the law.”