Description Mergal® BZ55 is a broad-spectrum wet-state preservative used to prevent deterioration and degradation of aqueous systems caused by bacteria, fungi, and yeast. Application & Use Mergal BZ55 is useful for the wet-state or in-can protection of various waterborne end-use products, such as paints, coatings, polymer emulsions, adhesives, sealants, mineral slurries, pigment dispersions, and other industrial applications. The preservative is suited for waterborne systems.