Approximately 30% of health care workers (HCWs) fail the respirator fit test. Evidence suggests that addressing face leaks in the 3M respirator enhances its fit and improves its efficacy. Between March 31 and April 9, 2020, HCWs who failed fit tests for 3M 1860 and 1860S respirators were invited to retest with an adhesive modification of the 3M respirator. Sixty-eight percent of HCWs who failed the fit test with their first-choice respirator passed with a modified adhesive respirator. To increase the efficacy and safety of 3M respirators, ineffective face seals need substantial improvement in design.