If a worker experiences difficulty breathing while wearing a respirator, it's crucial to act immediately. The worker should leave the hazardous area if possible, remove the respirator, and seek medical attention. Difficulty breathing could be a sign of a serious health issue, or it might mean the respirator isn't functioning correctly or is the wrong type for the job.

It's crucial to report such incidents to supervisors and have them documented. A follow-up should be done to determine the cause and take necessary measures to prevent a recurrence. This might involve re-evaluating the worker’s medical fitness to wear a respirator, conducting a new fit test, or reassessing the type of respirator used.