The arc resistant WL LVS standard design has extensive gasketing to prevent arc flash gases and debris from escaping the enclosure but not every cover and door is gasketed. Additional gasketing could be added at a cost but the use of internally mounted filters isn't allowed with arc resistant WL LVS. Externally mounted filters could be mounted in the rear of the LVS over the venting but couldn't be added at the top of the switchgear (at the vent stack).