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impossible to remove while the vessel is underway, and thus poses 

 an additional environmental threat. These properties clearly 

 indicate a long term need for alternative methods. 



There are also questions of safety concerning ballast water 

 exchange. When a vessel is exchanging ballast water, it may 

 become "light" and therefore susceptible to factors of wind, 

 waves, tide, and current. Additionally, ballast exchange puts a 

 strain on the hull and systems of a vessel, that over time may 

 create hazards to vessel operations such as the weakening of 

 structural members through flexing. While this is not a great 

 problem for the smaller vessels, there is no firm data on the 

 effect of ballast water exchange on larger vessels such as large 

 container ships and tankers. 



The Coast Guard believes that it is imperative that other methods 

 of ballast water management be developed, evaluated, and made 

 available as alternatives to exchange. A number of these have 

 already been identified as possible choices. They include 

 processing of the ballast water through filters to prevent the 

 passage of organisms, discharge to a reception facility, 

 ultraviolet light treatment, heat treatment, and the use of 

 chemical additives. Most if not all of these alternatives will 

 require some type of retrofitting to vessels. 



Discharging to a reception facility, while sounding simple, may 

 not be a particularly viable option at this time. There 



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