This should include prompt attention to employees experiencing discomfort or expressing other concerns. The chemical fume hood is a critical engineering control for minimizing airborne exposure to hazardous materials. The flow of air through the fumehood protects the user from fumes, vapors and mists generated during experiments. When the airflow is blocked or disrupted full protection fails and there is a potential for chemical exposure. Fume hoods are designed to ensure a constant stream of air over the work surface.
Air is pulled through the sash opening and across the work surface.
As the air passes over the work surface, it mixes with any fumes or vapors that are present. The air is exhausted through the baffles located at the back of the hood and then to the exterior of the building. Fume hood flow indicators, if present, should be monitored to determine if there is a change in face velocity. Disruption of the airflow can result in the potential for chemical exposure. Leaving loose, lightweight items, such as laboratory towels, in the hood where they can get sucked into baffles.