Types of Chemicals in the Workplace
The physical form of a chemical can affect how it enters your body and to some extent, the damage it causes. The main physical forms of chemicals are solids, dusts, liquids, vapours and gases.

 Solids

  • Solids are the least likely of the chemical forms to cause chemical poisoning. However, certain chemical solids can cause poisoning if they get onto your skin or food and you then ingest them. Personal hygiene is important to prevent the ingestion of chemical solids.
  • The greatest danger with solids is that some work processes can change them into a more dangerous form. For example, wood that is being cut can turn into wood dust which can then be inhaled. Welding rods can decompose into fumes and gases. Polyurethane foam is safe in its normal solid form but gives off deadly gases if it burns.
  • Chemicals in solid form can give off toxic vapours which can be inhaled, and solids can be flammable and explosive, and corrosive to the skin.
  • Effective control measures should be used with chemical solids, particularly during work processes which may change them into more hazardous materials.

Chemicals can change their physical form, e.g. wood into sawdust.
    
Dusts

  • Dusts are tiny particles of solids.
  • You can be exposed to dust in the workplace from materials that normally exist in dust form (for example, bags of cement), or from work processes that create dust (for example, handling glass fibre can produce toxic dust).
  • The main danger from harmful dusts is that you can breathe (inhale) them into your lungs. When breathed in, the larger dust particles are usually trapped by hairs and mucus and then removed by the body. Smaller particles, however, are more dangerous because they can get deep inside the lungs where they can have damaging effects, or they can be absorbed into the bloodstream and travel to other parts of the body where they can cause damage. They can also cause eye damage.
  • Dusts can be hard to see — you often cannot even see a cloud of tiny dust particles except with special lighting.
  • Under certain conditions dusts can explode. An example of this is an explosion in a grain silo or flour mill.
  • Effective control measures should be used to keep dust in the workplace at “safe” levels.

 Liquids

  • Many hazardous substances, such as acids and solvents, are liquids when they are at normal temperature.
  • Many liquid chemicals give off vapours which you can inhale and which may be highly toxic, depending on the chemical.
  • Liquid chemicals can be absorbed by your skin. Some liquid chemicals may cause immediate skin damage (they may or may not be absorbed into the bloodstream as well). Other liquids pass directly through the skin into the bloodstream, where they can travel to different parts of the body and cause damaging effects.
  • Effective control measures should be used with liquid chemicals to eliminate or reduce the possibility of inhalation, skin exposure and eye damage.

Vapours

  • A vapour is the gas phase of a material which is normally liquid under standard conditions.
  • Tiny droplets of liquid which are suspended in the air are called mists.
  • Many liquid chemicals evaporate at room temperature, which actually means that they form a vapour and stay in the air.
  • The vapours from some chemicals can irritate your eyes and skin.
  • There can be a variety of serious health effects from inhaling certain toxic chemical vapours.
  • Vapours can be flammable or explosive. To avoid fire or explosion, it is important to keep chemicals that vaporize away from any sparks, sources of ignition or incompatible chemicals.
  • Controls should be used to prevent worker exposure to vapours from liquids, solids or other chemical forms.
  • Gasoline and water are two examples of liquids which generate vapour under standard conditions.

Gases

  • Some chemical substances are in the form of a gas when they are at a normal temperature. However, some chemicals in liquid or solid form become gases when they are heated.
  • You can detect some gases easily by their colour or smell, but there are other gases that you cannot see or smell at all — you can only detect them with special equipment.
  • Gases can be inhaled.
  • Some gases produce irritant effects immediately. The health effects of other gases may be noticeable only after your health has already been seriously damaged.
  • Gases may be flammable or explosive. Extreme caution should be used when working around flammable or explosive gases.
  • Workers should be protected from the potential harmful effects of chemical gases with effective control measures in the workplace.
  • Some examples of gases are: nitrogen, nitrogen dioxide, carbon monoxide, carbon dioxide, and oxygen.

Effects of chemicals on the environment
Many employers are not aware of the hazards associated with toxic chemicals and often do not know how to dispose of chemical wastes safely. (Employers also need to be educated about chemical hazards.) As a result, these employers often simply “dump” waste chemicals into the environment. Convenient dumping grounds are the ocean, rivers, lakes, fields, roadsides, etc. Sometimes these dumping grounds are right in the community where you and your family live and work.Toxic chemicals which are improperly disposed of may eventually end up in your drinking water, in the places where your children play, in the soil where your food is grown, etc.

In reality, every country is struggling today with the problem of chemical waste and how to dispose of it permanently yet safely. The best solution to date is to use specially approved and well-maintained disposal sites that prevent chemicals from leaking into groundwater and into residential or farming areas. Dumping chemicals into the ocean is never a solution. In fact ocean dumping can have very serious effects - chemicals can get into the food chain, destroy marine life, wash back to shore, etc.