Which of the following are not local exhaust devices?

Unvented flammable liquid storage cabinets are considered safe storage solutions but do not qualify as local exhaust devices. Local exhaust devices are specifically designed to capture and remove contaminants directly from the source before they can mix with ambient air, thus minimizing exposure to potentially harmful vapors, fumes, or particulates.

In contrast, a chemical fume hood, canopy hood, and biosafety cabinet are all well-established local exhaust devices. A chemical fume hood efficiently removes hazardous fumes and vapors generated during chemical processes. A canopy hood operates over equipment to capture upward-dispersing contaminants effectively. A biosafety cabinet is designed to protect both the user and the environment from biohazards by filtering airflow while providing a sterile working area.

Understanding the function of different devices clarifies why unvented flammable liquid storage cabinets, which merely store chemicals and do not have ventilation systems to expel dangerous vapors, do not provide the same level of safety as the other options.