Fume scrubbers are optimally designed to save space, as well as provide effective air pollution control and operator safety protection for fume hoods. This is especially important for perchloric acid fume hoods, so as to prevent a build-up of potentially explosive perchlorate salts on the exhaust fan, as well as on the exhaust ducting system. Contaminated exhaust fumes from the fume hood enters the unit, passes through the packed bed (bottom filter), then through the liquid spray section, a mist eliminator (top filter), then into the exhaust system for release to the building exterior. The scrubbing liquor is collected in the reservoir in the bottom section and is recirculated by the pump back to be used in the liquid spray section. The exhaust fumes and the scrubbing liquor pass in a counter current fashion, resulting in efficient gas/liquid contact.