Chapter 4-PREVENTIVE AND CORRECTIVE DAMAGE CONTROL 



are required to work in contaminated areas. 

 The purpose of biological decontamination is to 

 destroy the biological agents. The purpose of 

 chemical decontamination is to remove or neu- 

 tralize the chemical agents so that they will no 

 longer be a hazard to personnel. 



Decontamination operations may be both dif- 

 ficult and dangerous, and personnel engaged in 

 these operations must be thoroughly trained in 

 the proper techniques. Certain operations, such 

 as the decontamination of food and water, should 

 be done only by experts qualified in such work. 

 However, all members of a ship's company 

 should receive adequate training in the elemen- 

 tary principles of decontamination so that they 

 can perform emergency decontamination oper- 

 ations. 



After an attack, data from NBC surveys will 

 be used to determine the extent and degree of 

 contamination. Contaminated personnel must be 

 decontaminated as soon as possible. Before 

 decontamination of installations, machinery, and 

 gear is undertaken, appraisals of urgency must 

 be made in light of the tactical situation. 



Radiological Decontamination 



Radiological decontamination neither neu- 

 tralizes nor destroys the contamination; instead, 

 it merely removes the contamination from one 

 particular area and transfers it to an area in 

 which it presents less of a hazard. At sea, 

 radioactive waste is disposed of directly over 

 the side. At shore installations, the problem is 

 more difficult. 



Several methods of radiological decontami- 

 nation have been developed; they differ ineffec- 

 tiveness in removing contamination, in appli- 

 cability to given surfaces, and in the speed with 

 which they may be applied. Some methods are 

 particularly suited for rapid gross decontami- 

 nation; others are better suited for detailed 

 decontamination. 



GROSS DECONTAMINATION.-The purpose 

 of gross decontamination is to reduce the radia- 

 tion intensity as quickly as possible to a safe 

 level— or at least to a level which will be safe 

 for a limited period of time. In gross decon- 

 tamination, speed is the major consideration. 



Flushing with water, preferably water under 

 high pressure, is the most practicable way of 

 accomplishing gross decontamination. Aboard 

 ship, a water washdown system is used to wash 

 down all the ship's surfaces, from high to low 



and from bow to stern. The washdown system 

 consists of piping and a series of nozzles which 

 are specially designed to throw a large spray 

 pattern on weather decks and other surfaces. 

 The washdown system is particularly effective 

 if it is activated before the ship is exposed to 

 contamination; a film of water covering the 

 ship's surfaces keeps the contaminating mate- 

 rial from sticking to the surfaces. Figure 4-9 

 shows a water washdown system in operation. 



Manual methods may be used to accomplish 

 gross decontamination, but they are slower and 

 less effective than the ship's washdown system. 

 Manual methods that may be used by ship's 

 force include (1) firehosing the surfaces with 

 salt water, and (2) scrubbing the surfaces with 

 detergent, firehosing the surfaces, and flushing 

 the contaminating material over the side. Figure 

 4-10 shows men performing gross decontami- 

 nation operations by manual scrubbing. 



Steam is also a useful agent for gross de- 

 contamination, particularly where it is neces- 

 sary to remove greasy or oily films. Steam 

 decontamination is usually followed by hosing 

 with hot water and detergents. 



DETAILED DECONTAMINATION.-As time 

 and facilities permit, detailed decontamination 

 is carried out. The main purpose of detailed 

 decontamination is to reduce the contamination 

 to such an extent that only a minimum of 

 radiological hazard to personnel would persist. 



Three basic methods of detailed decontami- 

 nation may be used— surface decontamination, 

 aging and sealing, and disposal. Each of these 

 methods has a specific purpose; one method can 

 often be used to supplement another. Surface 

 decontamination reduces the contamination with- 

 out destroying the utility of the object. In aging 

 and sealing, radioactivity is allowed to decrease 

 by natural decay and any remaining contamina- 

 tion is then sealed onto the surface. The disposal 

 method merely consists of removing contami- 

 nated objects and materials to a place where 

 they can do little or no harm. 



Biological Decontamination 



The methods available for biological decon- 

 tamination include scrubbing, flushing, heating, 

 and the use of disinfectant sprays, disinfectant 

 vapors, and sterilizing gases. The method to be 

 used in any particular case depends upon the 

 nature of the area or equipment to be decon- 

 taminated and upon the nature of the agent (if 

 this is known). 



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