This is Part Seven of a 13-part series of modules on HAZWOPER designed to provide the annual refresher training as required by OSHA for all employees affected by this regulation. Part Seven covers respiratory protection. Respirators provide vital protection against chemicals and oxygen-deficient atmospheres. For this reason it is critical to know how to select and use the appropriate respirator for the job. All respirators are not created equal: not all of them will provide protection in atmospheres with low oxygen or certain other atmospheric hazards. In this module, those with a role in hazardous waste operations and emergency response will learn how to protect themselves from the breathing hazards they may face.