1. Exposure to Hazards

2. Introduction
Chemicals have become part of all our lives. They are involved in daily activities. The workplace is not the only place where you are exposed to chemicals. Hazardous materials surround us and enter our bodies causing, in some cases significant harm.

3. How Hazardous Materials Enter the Body
There are three principle ways that hazardous materials enter the body:
Inhalation
Absorption
Ingestion

4. Inhalation
More hazardous agents get into your body by inhalation (by being breathed in) than by any other route. Hazardous materials in the form of:
Dust
Mist
Fumes
Gas
Vapour
Smoke
can be inhaled directly some-times without the individual even being aware. In addition, cigarettes can be contaminated by dirty hands leading to inhalation of hazardous materials.

6. Points to remember about inhalation
More hazardous agents get into your body by inhalation than by any other route of entry.
Although your body filters many of the normal pollutants from the air you breathe, it cannot eliminate every type of contaminant.

7. 2. Small particles are difficult for the body to eliminate and can get deep into the lungs where they can cause respiratory problems.
3. Workers in dusty occupations are more susceptible to respiratory diseases than workers in non-dusty occupations.

8. 4. Chemicals, in their various forms, can be inhaled and damage various target organs as well as the lungs.
5. It is important to notice warning signals, such as smelling chemical odours. It is also important to notice if you stop smelling a chemical odour that you used to smell - you may be “accustomed” or used to the smell and not know that you are being exposed to the chemical.

9. Absorption Hazardous materials in the form of: Liquid Solid Dust
can be absorbed directly through the skin. Sweat sometimes aids the process of absorption. In addition, absorption can occur through the eye after splashes or from vapours.

11. Points to remember
Your skin is a major route of entry for hazardous substances in the workplace.
Chemicals can be absorbed through healthy skin into the bloodstream and transported to target organs where they can have damaging results
Exposure to chemicals, physical hazards and biological hazards in the workplace can result in occupational diseases and allergic reactions.

12. Ingestion
Hazardous materials can be ingested by swallowing particles in each of the forms listed:
Gas
Dust
Vapour
Fumes
Liquid
Solid

13. In addition, food can be contaminated by dirty hands leading to ingestion of hazardous materials.
Can you think of another way that hazardous materials enter the body?
Through the placenta

15. Points to remember about ingestion
Hazardous agents can enter the body by being ingested (swallowed).
Some ingested hazardous agents are neutralized in the stomach, while others are absorbed into the bloodstream and transported to target organs.

16. 3. Eliminating hazardous agents is the best method of preventing their ingestion. Other important methods of prevention are personal hygiene and ensuring workers have access to washing facilities, food storage and eating areas that are away from their work areas.
4. Vomiting and diarrhoea are ways the body tries to remove certain toxic substances from the digestive system.
5. Toxic materials may enter the body by more than one route, so be familiar with all routes of entry to prevent exposures.

17. Preventing Exposure to Hazardous Materials
The four main examples of personal protective equipment that can be worn to prevent exposure to hazardous materials include:
goggles
protect your eyes from:
2. gloves
protect your hands from:

18. 4. coveralls, and lab coats
3. face masks
protect your face from:
4. coveralls, and lab coats
protect your body from:

19. Chemical Exposure
The effect of chemical hazards on the body depends on two attributes:
toxicity: the ability of a chemical substance to cause a hazard
exposure: the degree to which a person has encountered the chemical hazard.

20. Exposure to a chemical hazard depends on two things:
the concentration of the chemical hazard
the duration of the chemical hazard.

21. If the effect has a rapid onset, it is called an acute effect
If the effect has a rapid onset, it is called an acute effect. An example is a burn. If the effect is more gradual, usually with a long delay between exposure and onset of symptoms, it is a chronic effect. An example is the onset of lung disease after long term exposure to asbestos. Both types of effect can be permanent.

22. Chemical Categories
Explanation/ Toxicity
Hazard (health risks)
Examples of Chemicals
Dry chemicals
Small particles that easily penetrate the lungs
Destroy lung tissue and cause lung cancer
Asbestos
Substances containing crystalline silica, such as sand, concrete, ceramics
Solvents
(Organic chemicals that are used to dissolve fats and grease)
Evaporate and ignite very easily. They enter the body through the skin or by inhaling fumes when burned.
Cause irritation of the skin. Dangers to the liver, kidneys, bone marrow, or nervous system
Benzene
Carbon tetrachloride
Carbon disulfide

23. Chemical Categories
Explanation/ Toxicity
Hazard (health risks)
Examples of Chemicals
Metals
May enter the body in the form of dust and fumes (in grinding or welding) or through the skin
May cause damage to the nervous system. May cause cancer, allergies or birth defects
Lead
Mercury
Nickel
Chromium
Potassium hydroxide
Acids and Bases
These are used as water solutions when treating or cleaning metals, and can splash skin
Acids corrode human tissues. Bases are caustic (burn or corrode skin).
Sulfuric acid
Phosphoric acid
Ammonia

24. Chemical Categories
Explanation/ Toxicity
Hazard (health risks)
Examples of Chemicals
Pesticides
Are used to destroy or control pests, and can enter the body in a variety of ways
Can accumulate and poison the environment
DDT
Insecticides