Abstract: A two-way tamper-proof vent arrangement especially constructed for food grade receptacles and tanks is disclosed. The vent arrangement includes inner and outer stainless steel inverted cup members which are nested together and are concentrically mounted on a bracket over a tubular vent opening in the receptacle or tank. The outer cup member has a lower circumferential edge which bears on the surface of the receptacle or tank surrounding the vent opening so that tubes or other instruments cannot gain access to the vent opening. The inner cup member has a lower circumferential edge spaced from the surface of the receptacle surrounding the vent opening. The outer cup member is provided with a plurality of small openings to permit the inflow and outflow of venting air along a labyrinth path formed by the inner and outer cup members between the exterior of the outer cup member and the vent opening.