New York City’s human-rights commissioner has opened an investigation into Amazon’s firing of a warehouse worker who participated in a protest against the company, a spokesperson confirmed to Business Insider.

Amazon fired Chris Smalls, an assistant manager at the company’s Staten Island, New York, facility on Monday evening after he helped organize a strike earlier in the day to protest Amazon’s health and safety policies following a colleague testing positive for coronavirus.

Smalls claimed he was fired in retaliation for his involvement in the protest, telling Business Insider in a statement: “Amazon would rather sweep a problem under the rug than act to keep workers and working communities safe.”

Amazon has denied Smalls’ accusations, saying it fired him for repeatedly “violating social distancing guidelines and putting the safety of others at risk” after it asked him to stay home on paid sick leave after he came into “close contact with a diagnosed associate with a confirmed case of COVID-19,” the company told Business Insider in a statement on Monday.