What causes workplace hazards?

Where do workplace hazards come from?

Workplace hazards can come from a wide range of sources.  General examples include any substance, material, process,practice, etc that has the ability to cause harm or adverse health effect to a person under certain conditions.

Workplace Hazards

Workplace hazards also include practices or conditions that release uncontrolled energy like:

An object that could fall from a height (potential or gravitational energy)

A run-away chemical reaction (chemical energy)

The release of compressed gas or steam (pressure; high temperature)

Entanglement of hair or clothing in rotating equipment (kinetic energy), or

Contact with electrodes of a battery or capacitor (electrical energy)

The employer must provide and maintain all the equipment that is necessary to do the work, and all the systems according to which work must be done, in a condition that will not affect the health and safety of workers.  Before personal protective equipment may be used, the employer must first try to remove or reduce any danger to the health and safety of his workers. Only when this is not practicable, should personal protective equipment be used.

The employer must take measures to protect his or her workers’ health and safety against safety hazards that may result from the production, processing, use, handling, storage or transportation of articles or substances, in other words, anything that workers may come into contact with at work.  

To ensure that these duties are complied with, the employer must:

Identify potential safety hazards which may be present while work is being done, something is being produced, processed, used, stored or transported.

The terminology used in occupational health and safety (OHS) varies, but generally speaking, a hazard is something that can cause harm if not controlled.  The outcome is the harm that results form and uncontrolled hazard.

A risk is a combination of the probability that a particular outcome will occur and the severity of the harm involved.  Hazard, risk and outcome are used in other fields to describe for example environmental damage, or damage to equipment. However, in the context of OHS, harm generally describes the direct or indirect degradation, temporary or permanent, of the physical, mental, or social well-being of workers.  Repetitively carrying out manual handling of heavy objects is a safety hazard.

Workplace hazards are often grouped into environmental hazards, environmental agents, physical hazards, physical agents, chemical agents, biological hazards and psychosocial issues.

Below is an illustration of a hazard and risk assessment procedure:

Hazard and Risk Assement Procedure

Manual handling

Manual handling differs from many other workplace hazards in two ways, it is an activity rather than a feature of the work environment, and the degree of risk is a function of the inter-relationship of a number of different risk factors.  The process of manual handling hazard identification involves identifying those manual handling activities where one or more risk factors are present, in other words, where a significant risk of injury exists.

Manual handling is defined in terms of an activity involving the use of force.  It should be apparent that the risk of injury is a function of a number of risk factors acting in combination.

The most common approach to addressing OHS problems involves adopting a risk management approach.  This usually involves a three-stage process of:

- Hazard identification

- Risk Assessment

- Risk Control


Workplaces need to be adequately ventilated.  Fresh, clean air should be drawn from a source outside the workplace, uncontaminated by discharges from flues, chimneys or other process outlets, and be circulated through the workrooms.

Ventilation should also remove and dilute warm, humid air and provide air movement, which gives a sense of freshness without causing a draught.  If the workplace contains process or heating equipment or other sources of dust, fumes, or vapours, more fresh air will be needed to provide adequate ventilation.

Windows or other openings may provide sufficient ventilation but where necessary, mechanical ventilation systems should be provided and regularly maintained.

Temperatures in indoor workplaces

Environmental factors, such as humidity and sources of heat in the workplace combine with personal factors, such as the clothing a worker is wearing and how physically demanding their work is, to influence what is called someone’s ‘thermal comfort’.

Individual personal preference makes it difficult to specify a thermal environment, which satisfies everyone.

Work in hot and cold environments

The risk to the health of workers increases as conditions move further away from those generally accepted as comfortable.  Isk of heat stress arises, for example, from working in high air temperatures, exposure to high thermal radiation or high levels of humidity, such as those found in foundries, glass works, and laundries.  Cold stress may arise, such as, from working in cold stores, food preparation areas and in the open air during winter.

Assessment of the risk to workers’ health from working in either a hot or cold environment needs to consider both personal and environmental factors.  Personal factors include:

- Body activity

- The amount and type of clothing

- Duration of exposure

Environmental factors include ambient temperature and radiant heat;  and if the work is outside, sunlight, wind velocity and the presence of rain.

An employer should provide the employee with the following support when assessing the risks and hazards:

Introducing engineering measures to control the thermal effects in a workplace environment, for example, heat effects, may involve insulating any plant, which acts as a radiant heat source, thereby improving air movement, increasing ventilation rates and maintaining the appropriate level of humidity.  The radiant heat effects of the sun on indoor environments can be addressed either by orienting the building so that it does not suffer from the effects of solar loading, or where this is not possible, by the use of blinds or shutters on windows. Where workers are exposed to cold and it is not reasonably practicable to avoid exposure you should consider, for example, using cab heaters in fork-lift trucks in dold stores;  restriction of exposure by, for example, re-organising tasks to build in rest periods or other breaks from work.

This will allow workers to rest in an area where the environment is comfortable and, if necessary, to replace bodily fluids to combat dehydration or cold.  If work rates cause excessive sweating, workers may need more frequent rest breaks and a facility for changing into dry clothing, medical pre-selection of employees to ensure that they are fit to work in these environments.


Lighting should be sufficient to enable people to work and move about safely.  If necessary, local lighting should be provided at individual workstations and at places of particular risk such as crossing points as traffic routes.  Lighting and light fittings should not create any hazard. Automatic emergency lighting, powered by an independent source, should be provided where sudden loss of light would create a risk.

Cleanliness and waste materials

Every workplace and the furniture, furnishings and fittings should be kept clean and it should be possible to keep the surfaces of floors, walls, and ceilings clean.  Cleaning and the removal of waste should be carried out as necessary by an effective method. Wast should be stored in suitable receptacles.

Workroom dimensions and space

Workrooms should have enough free space to allow people to move about with ease.  The volume of the room when empty, divided by the number of people normally working in it, should be at least 11 cubic meters.  All or part of a room over 3.0 m high should be counted as 3.0 m high. 11 cubic meters per person is a minimum and may be insufficient depending on the layout, contents, and the nature of the work.

Workstations and seating

Workstations should be suitable for the people using them and for the work they do.  People should be able to leave workstations swiftly in an emergency. If work can or must be done sitting, seats which are suitable for the people using them and for the work they do, should be provided.  Seating should give adequate support for the lower back, and footrests should be provided for workers who cannot place their feet flat on the floor.

Substance Toxicities

Material safety data sheet

A material safety data sheet is a means of transferring essential information on the hazards of handling a chemical substance during transport, storage and processing from the supplier to the handler.  It may also be used to transfer this information to institutions, services and other bodies that play a role in dealing with the chemical substances.

Chemical hazards

Hazardous chemical substances should not be handled unless the handler has obtained the appropriate information.  In terms of regulations promulgated under the Occupational Health and Safety Act (Act No. 85 of 1993) (R1449 of 6 September 1996; Government Notice No. 17403) it is compulsory for the supplier of any hazardous chemical substance to provide a material safety data sheet to any party which receives such a substance.

A chemical hazard arises from contamination with harmful or potentially harmful chemicals.  Dangerous goods, also called hazardous materials are:



Gasses that can harm people, other living organisms, property, or the environment.  They are often subject to chemical regulations.


Liquid is one of the three classical states of matter.  Like a gas, a liquid is able to flow and take the shape of a container, but, like a solid, it resists compression.  Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly constant density.  A distinctive property of the liquid state is surface tension, leading to wetting phenomena.

The density of a liquid is usually close to that of a solid, and much higher than in a gas.  Therefore, liquid and solid are both termed condensed matter. On the other hand, as liquids and gasses share the ability to flow, they are both called fluids.


The solid state is characterised by structural rigidity and resistance to changes of shape or volume.  Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire volume available to it like a gas does.  The atoms in a solid are tightly bound to each other, either in a regular geometric lattice, or in a less ordered structure.


As most gasses are difficult to observe directly with our eyes, we uniquely describe them through the use of four physical properties.  They are pressure, volume, number of particles and temperature.

Dangerous goods

Dangerous goods include materials that are:


Radioactive decay is the process in which an unstable atomic nucleus spontaneously loses energy by emitting ionizing particles and radiation.  The genetic effects of radiation, including the effects on cancer risk, were recognised much later.


Flammability is defined at how easily something will burn or ignite, causing fire, or combustion.  The degree of difficulty required to cause the combustion of a substance is subject to quantification through fire testing.  A variety of test protocols exist to quantify flammability.


An explosive material, also called an explosive, is a substance that contains a great amount of stored energy that can produce an explosion, a sudden expansion of the material after initiation, usually accompanied by the production of light, heat, and pressure.

Chemical explosives are substances that contain a large amount of energy stored in chemical bonds.  Explosives are classified as low or high explosives according to their rates of burn. Low explosives burn rapidly or deflagrate, while high explosives detonate.


Corrosive substance is one that will destroy or irreversibly damage another substance with which it comes into contact.  The main hazards to people include damage to the eyes, the skin, and the tissue under the skin, inhalation or ingestions of a corrosive substance can damage the respiratory and gastrointestinal tracts.  Exposure results in chemical burn.


Oxidizing, literally means converting to oxide.  This process can apply to metals (iron converts to iron oxide), non-metals (sulfur converts to sulphur oxide), and organic matter (mainly carbon and hydrogen converts to carbon oxide and hydrogen oxide.


Asphyxia is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally.  An example of asphyxia is choking. Asphyxia causes generalised hypoxia, which primarily affects the tissues and organs.

Bio hazardous

A biological hazard or biohazard is an organism, or substance derived from an organism, that poses a threat to primarily human health.  This can include medical waste or samples of a microorganism, virus, or toxin from a biological source that can impact human health. It can also include substances harmful to animals.  The term and its associated symbol are generally used as a warning, sot hat those potentially exposed to the substances will know to take precautions.


Toxicity is the degree to which a substance is able to damage an exposed organis.  An element is a chemical substance that is made up of a particular kind of atos and hence cannot be broken down or transformed by a chemical reaction into a different element, though it can be transmitted into another element through a nuclear reaction.

Workplace hazards are often grouped into environmental hazards, environmental agents, physical hazards, physical agents, chemical agents, biological hazards and psychosocial issues.  Below the different groups of workplace hazards are identified:

Workplace hazards

Environmental hazards - Asphyxiation, Dehydration

Environmental agents include - Cold stress (hypothermia), Heat stress (hyperthermia), Particulate inhalation

Physical hazards - Collisions, Confined space, Slips and trips, Falls from height, Struck by objects, Electricity, Falling on a pointed object

Physical agents - Noise, Vibration, Lighting, Barotrauma (hypobaric/hyperbaric pressure)

Ionising radiation.

Biological hazards - Bacteria, Virus, Fungi, Mold, Blood-borne pathogens, Tuberculosis

Mechanical hazards include:

Compressed air/high pressure fluids such as cutting fluid, Crushing, Cutting, Draw in,

Entanglement, Equipment-related injury, Friction and abrasion, Impact, Moving parts, Shearing, Stabbing and puncture, Workplace transport.

Chemical agents - Acids, Bases, Heavy materials, Solvents, Particulates, Fumes (noxious gases/vapours), Highly-reactive chemicals, Fire, conflagration and explosion hazards

Psychosocial issues - Work-related stress, whose causal factors include excessive working time and overwork, violence from outside the organisation, bullying, which may include emotional, verbal, and sexual harassment, mobbing.

To control hazards in the workplace they first need to be identified.  This can be done in three ways: Collecting information, checking records of accidents, medical and occupational hygiene reports and conducting an inspection of the workplace.

Posted date: 20th May 2019
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