A former nurse at Northwestern Memorial Hospital filed a lawsuit alleging she was fired after warning coworkers that masks the hospital provided did not adequately protect staff against COVID-19.

Lauri Mazurkiewicz filed the suit Monday in Cook County Circuit Court, naming the hospital and several employees as defendants, the lawsuit states.

According to the suit, the hospital began accepting and treating patients diagnosed with COVID-19 in March, allegedly exposing Mazurkiewicz and others to the virus.

Instead of distributing N95 masks, which are effective at preventing the wearer from contracting the virus, the hospital allegedly provided staff with “less-effective” masks, the lawsuit claims. The hospital allegedly also prevented its employees from wearing N95 masks.

Mazurkiewicz sent an email March 18 warning employees and supervisors that N95 masks were more effective than the masks distributed by the hospital, the suit states. She was fired the next day after showing up to work while wearing an N95 mask.

The lawsuit claims she was laid off in retaliation for warning staff that the masks the hospital provided were unsafe.

A spokesman for Northwestern Memorial said in an email that the hospital is “reviewing the complaint.”

The suit seeks a jury trial and more than $50,000 in damages.