OSHA's Temporary Enforcement Guidance - Healthcare Respiratory Protection Annual Fit-Testing for N95 Filtering Facepieces During the COVID-19 Outbreak, is very important - among other things, OSHA says to perform an initial fit test using a qualitative method, to suspend annual fit-testing requirements during the pandemic, but to perform user seal checks when the respirator is donned.
https://www.osha.gov/memos/2020-03-14/temporary-enforcement-guidance-healthcare-respiratory-protection-annual-fit
https://www.osha.gov/memos/2020-03-14/temporary-enforcement-guidance-healthcare-respiratory-protection-annual-fit