PPE CASE Notes Content source: National Institute for Occupational Safety and Health Personal Protective Equipment Conformity Assessment Studies and Evaluations (PPE CASE) Notes are fact sheets that provide a summary of findings from our post-market personal protective equipment tests, evaluations, and investigations. These fact sheets inform respirator users about common themes or trends we found and provide best practice reminders to prevent future occurrences. PPE CASE Notes Personal Protective Equipment Conformity Assessment Studies and Evaluation Notes: Firefighter SCBA Facepiece Sizing Issues DHHS (NIOSH) Publication No. 2020-107 Respirators used in the workplace need to be approved by the National Institute for Occupational Safety and Health (NIOSH). When users experience issues with NIOSH-approved respirators, NIOSH initiates a Certified Product Investigation Process to identify the root cause and develop corrective actions. Below is an example of a past issue that NIOSH addressed through this process. This example focuses on self-contained breathing apparatus (SCBA) facepiece sizing issues within fire departments.