Four ballast water treatment system manufacturers have received the final agency action from the United States Coast Guard denying their appeals to use an alternative testing method for Coast Guard type approval of their ultra-violet (UV)-based ballast water management systems (BWMS).

In December 2015, the manufacturers were declined the use of the alternative testing method as the USCG Marine Safety Center’s (MSC) initial review concluded that the requested most probable number (MPN) method does not meet the requirements for an alternative method stipulated in the regulation.