release toxic gases or explode. If you handle lithium batteries, observe the following safety precautions to prevent   injuring   yourself   and   damaging   your equipment:    Use only lithium batteries that are approved for use in your equipment.    Store  lithium  batteries  in  cool,  well-ventilated areas away from flammable items.    Always   observe   polarity   when   you   install lithium batteries.    NEVER  pierce,  short-circuit,  recharge,  crush, cut, burn, drop, dismantle, modify, or otherwise carelessly handle lithium batteries.    NEVER   leave   lithium   batteries   in   equipment that will not be used for long periods of time.    NEVER  throw  lithium  batteries  in  daily  trash. D i s p o s e o f t h e m p r o p e r l y. S e e t h e Environmental and Natural Resources Program Manual,   OPNAVINST   5090.1,   for   more disposal information on lithium batteries. Nickel-Cadmium Cell Battery C o m m o n l y k n o w n a s a N I C A D , t h e nickel-cadmium   battery   is   used   in   most   cordless, rechargeable equipment, such as flashlights, cordless drills, soldering irons, and portable stereos. The following safety precautions for NICADs are relatively simple:    Charge NICADs in series, never  in parallel.    Follow   the   manufacturer’s   instructions   for charging NICADs.    NEVER  expose  NICADs  to  temperatures  over 113 degrees Fahrenheit (45 degrees Celsius).    NEVER short-circuit NICADs.    NEVER  store  NICADs  and  lead-acid  batteries in the same container or in the same area.    N E V E R   d i s p o s e   o f    b y   t h r ow i n g   t h e m overboard. Store exhausted cells temporarily in a plastic-lined   steel   container   until   you   can dispose   of   them   properly   ashore.   See   the Environmental and Natural Resources Program M a n u a l , O P NAV I N S T   5 0 9 0 . 1   ( S e r i e s ) Appendix L. VACUUM TUBES There  are  two  basic  categories  of  vacuum  tubes: (1)  electron  tubes,  and  (2)  cathode-ray  tubes.  As  for other  hazardous  materials,  you  must  follow  certain safety   precautions   when   you   work   with   or   handle vacuum tubes. Electron Tubes Electron tubes are fairly rugged devices. Most of them  can  handle  the  shocks  and  knocks  of  everyday use.   However,   they   are   not    indestructible.   Most electron   tubes   contain   a   near   vacuum   enclosed   by glass. Any excessive stress, like dropping the tube, may cause the glass to shatter, causing an implosion (burst inward). An implosion is the opposite of an explosion. When the glass shatters, the outside air rushes into the tube to fill the vacuum. As the air rushes into the tube, it carries the glass fragments with it, right on through the center of the tube and out the other side. If you are in the path of these flying fragments, you may be injured seriously. So, handle all electron tubes with care. Some electron tubes contain radioactive material to  aid  ionization.  These  must  be  handled  with  extra care.  Unbroken,  the  radioactive  tubes  are  as  safe  as other electron tubes because the radioactive material in the   tube   emits   slow-moving   particles   that   are contained   within   the   tube’s   thick   glass   envelope. However, breaking the tube will expose the hazardous radioactive material. To  avoid  injuring  yourself  or  others,  observe  the following  safety  precautions  when  you  handle  either regular or radioactive tubes:    Handle all electron tubes, whether radioactive or not, with extreme care.    Immediately  place  any  electron  tube  that  you remove,   whether   radioactive   or   not,   into   a protective   container,   such   as   its   shipping container.    Inform   your   supervisor   immediately   if   you break a radioactive electron tube.    Seal   off   a   radioactive-contaminated   area immediately to avoid exposing other personnel to the radioactive material.    Treat  all  bad  or  damaged  radioactive  electron tubes as radioactive waste and dispose of them accordingly. 4-7