Abstract: A flame retarding filter device is disclosed for use in an air exhaust system wherein the exhaust air carries grease particles and the like susceptible to combustion. The device has first and second rows of spaced parallel baffle elements each of which has a generally planar central portion and inclined longitudinal edges. The rows of baffle elements are supported in spaced relation with the baffle elements of the rearward row overlying the spaces between the baffle elements of the front row in a manner to retard the passage of flames through the device while allowing sufficient free flow of air through the unit to exhaust heat and odors from the room in which the device is employed.