Lesson 1, Topic 1
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1.4. Types Of Hazards

ryanrori July 14, 2020

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1.4. Types of Hazards Encountered In the Workplace

The OHS Act defines a hazard as “a source of or exposure to danger” and a risk as ”the probability that injury or damage will occur.”  Each hazard thus has risk(s) involved.  If you don’t disconnect the electricity supply before working on an electrical appliance you run the risk of being electrocuted.

The degree of risk involved varies according to the situation.  When using a sharp knife to peel an apple, a two year old toddler will run a much greater risk of cutting himself than an adult performing the same exercise.

Safe, according to the OHS Act means free from any hazard”.

Hazards will differ from work place to work place, and they could be the following, depending on the circumstances.

For better understanding we will group hazards as follows:

1.4.1. Physical Hazards

These hazards can harm the body and/or influence or stop the effective functioning thereof.

Examples include:

Fire and explosion

The hazard is the fire, where you are exposed to danger, while the risk is that the fire can cause severe burns and injuries.

Flammable liquids used unsafe, chemicals that are mixed that react with each other. Striking a match when smelling gas, wrongly installed gas installations and many other examples. A experiment will be conducted to illustrate this.

Extreme heat

Working in a steel mill or very deep underground: The hazard is the extreme heat and the risk is injury due to heat exhaustion. Excessive heat can cause a strain on the heart and circulatory system, cramps, heat exhaustion, heat stroke and death of exposure and exertion.

  • For hot environments, reflective clothing can be used effectively to protect workers from radiant heat and extraordinary hot environments. Such garments are used widely in the steel industry, foundries and other hot metal industries. Coats, pants, coveralls, and hoods are also available.
  • In hot climates, there must also be sufficient air circulation; workers must use heat shields or barriers; and finally, workers must replace body fluids regularly which have been lost due to heat.

Extreme cold

Working outdoors in winter or in a cold room: The extreme cold is the hazard while the risk is injury due to frost bite. Extreme cold can cause frostbite and the destruction of tissue  extended exposure to extremely low temperatures can even cause death.

  • For cold environments, employees should be equipped with proper clothing,
  • they should keep themselves healthy and
  • they should never work alone, but always in pairs


Working with pneumatic (powered by compressed air) tools and equipment such as drills and jackhammers or being a member of The Rolling Stones.  The hazard is the loud noise, while the risk is damage to your hearing due to the loud noise.


From exposure to arc welding, X-rays or radioactive material. Being exposed to radiation is a hazardous condition and the risk is damage to your health due to the radiation.

For example, ionising radiation which can cause anaemia, sterility, leukaemia, bone damage, damage to unborn children, genetic damage, tumours, cataracts and shortening of the lifespan; non-ionising radiation such as infra-red and ultraviolet radiation, microwaves, lasers and visible light can produce burns or excessive heating of the skin and tissues just below it. The burns produced vary in their severity according to the extent of the exposure.


Drowning and flooding.  Water is the hazard and the risk is drowning.

Extreme physical conditions

Continuous vibration experienced by drivers of heavy vehicles, the effect of extreme g-forces on fighter- and aerobatic pilots, the effect of high pressure on divers, etc.  The physical conditions are the hazards and the risks are injury due to the hazards.


Electricity is one of the main causes of injuries and fires in the workplace. DO NOT work with faulty electrical equipment, DO NOT work on equipment before isolating the electricity and use the correct lockout procedures.

Mechanical devices

Mechanical devices such as hand mixers, hand operated food processors, which can injure workers if not operate properly.


Pressure cookers in kitchen have caused many accidents in the past. Many working environments use steam for cooking purposes and extreme caution should be taken when working with this medium for many burs are caused by steam operating equipment. Gas bottles are also classified as pressure vessels and can cause burns and explosions.

Tools and equipment

Tools and equipment used in the kitchen such as knifes, blenders, stoves, refrigeration, microwave ovens, food processors, extraction fans, and many more can be potential dangers if not properly operated. Safe working procedures must therefore be introduced for each and every task in the profession of the worker for the task to be performed.

Vehicles and machinery

In accordance with the O H S act every worker must be trained for the specific job that he/she performs or is. In some cases a worker is not allowed to operate a machine or a vehicle without a special license after undergoing training by an accredited company and found competent to operate the machine or vehicle, and a special license must be issued. These examples can be lifting equipment, forklift trucks and motor vehicles and trucks.

Welding, cutting and grinding operations

Welding can cause severe harm to the eyes of the welder if the proper PPE is not used during the performance of the task. This does not only comply with the welder but also the workers working in the same area. This can be overcome by either the workers wearing the same PPE as the welder or by leaving the area where the welding takes place. Grinding and cutting is as dangerous to fellow workers as to the worker performing the job. The reason is that during grinding and cutting small parts of the material that is worked on can be flung in fellow workers eyes and can cause severe injury or permanent disablement.

Working at heights and excavations

Proper training must be must be given to workers before performing these tasks. These tasks include working on ladders, scaffolding, heights and trenches that have been dug. Ladders can be dangerous if not in good working order and inspected regularly, if scaffolding has no firm base were it is erected it can collapse, and if special precautions are not taken when trenches are dug, collapse of the side walls can cause workers to be buried alive if the side walls collapse.

1.4.2. Chemical Hazards

Chemicals such as cleaning agents can be corrosive, flammable and even explosive. Chemicals that are not used in the correct prescribed manner as stipulated by the manufacturer can be dangerous and even fatal to the user.

There are many categories of chemicals, each with unique properties and potential hazards.

Examples include:


Sulphuric acid, “spirits of salts”, pool acid, etc. are highly corrosive and can cause severe burns.  The nitrous fumes caused when nitro-glycerine based explosives like dynamite explode contain enough nitric acid to burn and cause blistering inside the lungs if inhaled, often with fatal results if not treated timely, as the blisters burst and fills the victim’s lungs with liquid and he drowns.  So, the hazard would be the presence of acid and the risk is injuries caused by inhaling the acid.


Caustic soda, soda ash, etc, are also very corrosive and can cause severe burns.  Caustic soda is a hazard and the risk is injury if it comes into contact with

the human body.

Air pollution

Harmful gases and dust is often released into the atmosphere and breathed in by living creatures or carried over great distances and deposited as acid rain, affecting life. Examples include: dust, fumes, smoke, mist, gases, vapours, free silica and asbestos

Water pollution

Toxic chemicals are released into river systems with disastrous effect on life and the environment.

1.4.3. Biological Hazards

Biological hazards involve living organisms, like bacteria, spores, fungi, etc.

Examples include:

  • Infections caused by bacteria, fungi, parasites, etc. The bacteria is the hazard and the risk is infection when it enters the human body.
  • Farm workers and animal handlers get infections from animals. The hazardous condition exists when working with farm animals and the risk is infection due to handling the animals.
  • Health workers get infected through exposure to used needles, inhaling or swallowing bacteria or viruses. A used needle is a hazard that becomes a risk when it is used.
  • Sewage or waste disposal workers are continuously exposed to bacteria and viruses. Sewage is a hazard and the risk is infection when you come into contact with it.

1.4.4. Ergonomic Hazards

These hazards relate to how “worker friendly” the worker’s working environment is.  Working under unfavourable conditions can cause discomfort and injury.  Factors like having to stand for long periods, working in cramped spaces, not having adequate ventilation, etc. can all cause discomfort and eventual injury.  The hazard is present in the working condition and the risk is the injury that could happen as a result of the hazard.


Illumination is also an ergonomic hazard. For example, employers should attend to burnt out globes; defective fluorescent tubes; light fixtures covered with dirt, grease, or oil; little or no provision for emergency lighting; unlighted or dimly lit exits;

Temporary lighting that has become permanent through oversight; and poorly-placed lighting sources that cast shadows in the employee’s work areas.

Confined spaces

Areas, which are very small, or ventilation is inadequate, resulting in dangerous circumstances.


Proper ventilation is essential to a good environmental health programme. Adequate ventilation and air replacement are necessary for employee health and wellbeing. One should take advantage of the natural air movement by opening windows or roof monitors. Do not allow ventilation methods to permit noxious fumes or dust to enter the factory environment from other nearby factories.

1.4.5. Psychosocial Hazards

This normally goes hand in hand with stress and tension in the workplace.  A disgruntled worker might be so upset that it affects his ability to concentrate properly.  If he works with dangerous machinery or equipment his lack of concentration may cause him to overlook safety precautions, resulting in injury or damage to property. working with machinery is hazardous and the risk is injury or damage to property if the machine is not operated safely.

1.4.6. Hazardous substances

Substance” includes any solid, liquid, vapour, gas or aerosol, or combination thereof.

Examples are

  • inorganic materials such as lead, mercury, arsenic, cadmium, and asbestos
  • and organic substances such as polychlorinated biphenyls (PCBs), vinyl chloride, and the pesticide DDT, benzene