CHICAGO (Chicago Sun-Times) — A former nurse is suing a Chicago hospital for allegedly firing her in retaliation for warning colleagues that masks provided by the hospital to treat COVID-19 patients would not sufficiently protect them.

The Chicago Sun-Times reports that Lauri Mazurkiewicz contends in her lawsuit filed Monday that Northwestern Memorial Hospital began accepting COVID-19 patients this month but gave employees “less-effective” masks and prevented them from wearing more effective N95 masks.

A hospital spokesman said in an email to the newspaper that the hospital was reviewing the complaint.