• If mechanical ventilation is used, measurements must be made to demonstrate its effectiveness.

If mechanical ventilation is used to control exposure, measurements that demonstrate the effectiveness of the system in controlling exposure, such as capture velocity, duct velocity, or static pressure, must be made as necessary, to maintain the system’s effectiveness. Any change in production processes or controls that might increase cadmium exposure requires the effectiveness of the ventilation system to be reevaluated within five working days of the change. If air is recirculated from exhaust ventilation into the workplace, the system must be equipped with a high-efficiency filter and be monitored periodically to ensure effectiveness.