User safety and comfort is paramount with all Class II Biological Safety Cabinets. This new design cabinet features an ergonomically-designed operating window that slants away from the operator. A feature which greatly enhances the new cabinets ease of use without compromising the clean integrity of the work zone. Dual fan design for guaranteed safety. If one fan fails, minimal protection is still maintained with only one fan running. Independent H14 HEPA supply and exhaust filters provide 99.999% typical efficiency for particle sizes of 0.1 to 0.3 microns. A backup battery maintains alarm function for airflow, power and pressure alarm in the event of a power failure. In operation, vertical laminar airflow through a HEPA filter bathes the work tray, dividing and passing around the perimeter to create a biologically clean work area. An air barrier across the work access opening, into the sump, reduces potential risks to personnel from airborne contaminants in the work zone. A microprocessor is used to control the speed of the blower motors.