the preparation of water for large numbers, the boiling  procedure  should  be  supervised.  Water boiling  may,  of  necessity,  become  an  individual responsibility  and  may  be  so  directed. For small groups of people, the Lyster bag is provided  as  a  suitable  container  for  the  storage of water that has already been treated for use in the purification process. Water that has not been made potable previously is purified in the Lyster bag  by  means  of  chemicals.  Water  purification procedures are discussed in detail in chapter 11 of the  HM 3 & 2  Rate   Training   Manual. Food In the event of a known or suspected biological attack,  all  exposed  or  unpackaged  foods  not  in critical  supply  should  be  destroyed.  In  most instances,  food  can  be  rendered  safe  for  con- sumption  by  application  of  moist-heat  cooking procedures.  In  some  instances,  deep  fat  cooking  is adequate.  Some  foods,  however,  cannot  be sterilized  because  the  treatment  would  render  them unacceptable   for   consumption. DECONTAMINATION The  extent  to  which  personal  decontamination can be carried out following actual or suspected exposure  to  biological  agents  will  depend  upon the  existing  tactical  situation  and  the  facilities available.   If   the   situation   permits,   con- taminated  clothing  should  be  carefully  removed and  the  body  washed  thoroughly  with  soap  and water   before   donning   fresh   clothing.   Specific attention  should  be  given  to  decontamination  and the  treatment  of  skin  lesions. Normally,  each  individual  is  responsible  for his  or  her  own  decontamination.  If  a  person  is physically  unable  to  decontaminate  himself  or herself, this process has to be performed by other available personnel, including medical personnel. Since illness resulting from exposure to biological warfare  may  be  delayed  because  of  the  incuba- tion  period,  decontamination  may  occur  before the   individual   becomes   ill.   Decontamination of  the  wounded,  however,  will  not  have  been carried  out  and  is  the  responsibility  of  Medical Department  personnel.  In  the  management  of  the wounded, a problem of priority may exist. When the  situation  and  the  condition  of  the  casualty permit,   decontamination   should   come   first. However,  massive  hemorrhage,  asphyxia,  or  other life-endangering  conditions  naturally  receive priority. In  general,  all  candidates  for  decontamination should  first  have  all  exposed  areas  thoroughly washed  with  soap  and  large  amounts  of  water, the mask adjusted, and all contaminated clothing removed.  The  casualty  may  then  be  moved  to  a clean  area  where  the  wounds  can  be  treated. Decontamination procedures are the same as those  used  for  casualties  of  chemical  warfare. RADIOLOGICAL  DEFENSE Teams  entering  contaminated  areas  to  remove casualties and those working in decontamination stations  have  two  major  concerns.  One  is  the prevention  of  their  own  contamination  and  the other   is   preventing   or   reducing   radioactive exposure.    Contamination  can  be  avoided  by decontaminating patients and equipment prior to handling,  wearing  appropriate  protective  clothing and   equipment,   avoiding   highly   contaminated areas,   and   strictly   observing   personal   decon- tamination   procedures.   Exposure   to   radiation should  also  be  avoided  or  minimized.  Alpha and beta particles and gamma rays are emitted from   radioactive   contaminants   and   present   a direct risk to the health and safety of personnel in the contaminated area. This risk can be avoided or minimized by following some simple guidelines and  using  common  sense.  Time,  distance,  and shielding  are  the  major  principles  that  guide actions  to  avoid  exposure. Radioactive   decay   and   the   deposition   of fallout  products  progresses  rapidly  in  the  early hours  after  a  nuclear  blast,  and  the  hazards  to rescue  workers  can  be  reduced  considerably  if operations  can  be  delayed  until  natural  decay has  reduced  the  level  of  radioactivity.  If  teams trained  in  the  use  of  survey  instruments  are available,  guesswork  can  be  eliminated  since  they will determine the intensity of radiation with their instruments and mark perimeters of danger zones. Limiting  the  time  of  exposure  is  essential  if total avoidance is not possible. Rotating person- nel  entering  an  exposure  risk  area,  planning actions to minimize time in the area, and prompt decontamination  reduce  the  total  time  the  in- dividual  is  exposed  and  therefore  reduces  the  dose of  radiation  absorbed  by  the  body. Both  radioactive  particles  and  electromagnetic waves  (gamma  rays)  lose  energy  and  consequently lose  their  ability  to  harm  tissue  as  they  travel away  from  their  source.  Therefore,  the  further one is from the source, the danger of an exposure is  minimized. 6-5