ABSTRACT - 593570 The disclosure relates to a method of treating ballast water in a tank of a seagoing vessel comprising the steps of: (a) adding an effective amount of a suspension concentrate formulation of the compound 2-methyl-1,4-naphthalenedione to the tank, wherein preferably the suspension concentrate comprises 40 to 85 % of the compound 2-methyl-1,4-naphthalenedione and 7 to 9 % of a starch or dihydric alcohol and remaining amount of additives and a carrier (b) maintaining the ballast water in the tank for a time and at a temperature sufficient to devitalize harmful aquatic organisms and pathogens that may be present in the ballast water and then (c) expelling the ballast water from the tank to the exterior of the vessel.
