Elimination, substitution, engineering and administrative controls, and PPE; respirator selection, assigned protection factors, and fit testing (29 CFR 1910.134). General PPE program requirements (29 CFR 1910.132): the workplace hazard assessment and its written certification, PPE selection and proper fit, employee training (when and what PPE is necessary, donning/doffing and adjustment, the limitations of the PPE, and its care and maintenance) and retraining triggers, the prohibition on defective equipment, employee-owned equipment, and employer payment for PPE including the exceptions (non-specialty safety-toe footwear and prescription eyewear, and everyday clothing).
An employer uses air-purifying respirators with organic vapor cartridges to protect workers against benzene. If there is no end-of-service-life indicator (ESLI) certified for benzene, what is the mandatory minimum frequency for replacing these cartridges?