danger from the vapors, direct contact with many materials,  such  as  etchant  acids,  radiographic solutions,  endodontic  materials,  or  bleaching  agents can cause chemical burns of the skin or eyes. Chemical Storage Proper storage of chemicals is critical for safety. The  type  of  container  and  cabinet,  security,  and proximity to other chemicals, materials, heat, or open flame are areas that need consideration and control. How to Eliminate Hazards Proper ventilation can eliminate hazards associated with most gases and chemicals. Instructions must be written for the safe use, storage, clean up, and disposal of  hazardous  or  contaminated  items.  Storage  rooms must be properly furnished and maintained. Personnel protective equipment, such as a mask, shields, rubber gloves, rubber or plastic aprons, eyewear and eyewash stations must be available. Next we will discuss some of the specific chemicals used in dentistry and their precautions. Organic Chemicals Examples of organic chemicals include alcohols, ketones,  esters,  solvents,  and  monomers,  such  as methyl  methacrylate. When using these chemicals, you should avoid skin contact and excessive inhalation of vapors. Always work in a well-ventilated area with these  types  of  chemicals.  When  not  in  use,  keep containers tightly closed and stored on flat, sturdy surfaces. After each use, clean the outside surfaces of the  containers  to  prevent  residual  material  from contacting the next user. Radiographic  Chemicals These chemicals are used to process radiographs. When  handling  these  chemicals,  always  work  in well-ventilated  areas,  and  wear  protective  eyewear, plastic apron, and rubber gloves to avoid skin contact. When mixing the solution, minimize your exposure to the dry powder. If  spills  of  these  chemicals  occur, clean them up at once.   If you should come in direct contact with these chemicals, wash the chemicals off with large amounts of water and a pH-balanced soap. Store radiographic solutions and chemicals in tightly covered containers in a cool, dark place. Acid Etchants These solutions and gels are used for acid etch techniques.    When using or handling these products, always wear protective eyewear and rubber gloves to avoid  skin  contact.  Always  handle  acid-soaked  items with  forceps  or  gloves. If  spills  occur,  use  a commercial acid spill kit. in the event of eye or skin contact, rinse the area with large amounts of running water. Flammable Liquids Many  items  used  in  dentistry  are  flammable. Solvents such as acetone and alcohol are examples. When using flammable liquids, always have adequate ventilation, never use where sparks or flames are present, and have a fire extinguisher available. You must  store  flammable  liquids  and  bulk  quantities  in tightly covered containers in an approved flammable storage locker. Gypsum Products These products, which include dental plaster and stone, are considered hazards because of their powder form and of the dust particles created when they are in use. When handling the powder form or trimming cast, use protective eyewear, a mask, and work in areas with an exhaust system.   It is important to minimize your exposure to the powder during handling. MERCURY CONTROL To minimize personnel exposure and environ- mental contamination of elemental mercury in DTF’s, follow  the  handling  procedures  in  BUMEDINST 6260.30. Mercury, which vaporizes at room temperature, is a significant health hazard if a sufficient amount is ingested, absorbed through the skin, or inhaled. The potential for personnel exposure to elemental mercury vapor  has  been  greatly  reduced  by  the  use  of pre-encapsulated  amalgam. Because of the health hazard potential of mercury, control  procedures  for  the  handling  and  disposal  of amalgam,   or   mercury-contaminated   items   are mandatory. Dental amalgam is an inter-metallic compound comprised of various proportions of silver, copper, tin, and zinc alloy mixed with pure mercury. This mixture of  metals  forms  a  compound  that  is  stable  both 11-2