1. Enforcement policy for face masks and respirators during the coronavirus disease (COVID-19) public health emergency (revised): guidance for industry and food and drug administration staff Publication: [Silver Spring, MD] : Center for Devices and Radiological Health, May 2020 Subject(s): COVID-19 -- prevention & controlMasksN95 RespiratorsPersonal Protective EquipmentRespiratory Protective DevicesUnited StatesUnited States. Department of Health and Human Services.United States. Food and Drug Administration.