LAMINAR FLOW HOODS CRITERIA 1 Nothing should be permitted to come in contact with the HEPA filter. This includes __. __ should not be opened directly toward the filter. 2 Do not put __ into the hood. 3 __ should not be worn on the hands or wrists when working in the LAH since it may introduce bacteria or particles into the clean work area. 4 Actions such as__ should be directed away from the LAH working area, and any unnecessary motion within the hood should be avoided to minimize the turbulence of air flow.