Health Hazards Of Fly Ash Dust Environmental Sciences Essay

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Continual growth in the economy and an improvement in the standard of living are the main reasons for the sharp rise in electricity consumption in Mauritius in recent years. These have call for the upgrading of the transmission system and also substantial funds being invested in the energy infrastructure for the generation of power from oil, bagasse and coal.

In Mauritius, energy policy is design and implemented by the Ministry of Public Utilities (MPU). It is responsible for the power sector, the water and waste water sectors and administers the Central Electricity Board (CEB) which is the power utility. The CEB generates and supplies electricity, currently acts as the electricity regulator. The management and improvement of electricity supply in the whole island is carried out by the latter. As such, CEB is authorized to "perform development proposals with the aims of promoting, managing and ameliorating the transmission, generation, delivery and sale of electricity throughout Mauritius as required". Government policy for the generation of electricity is to encourage the use of local and renewable energy sources other than oil.

The CEB has experienced reforms and privatization in recent years, and with regards to this, approximately 60% of the country's power requirements is produced by the CEB and the remaining 40% is bought from Sugar Estates. The Independent Power Producers (IPP) is mainly the sugar estates exporting power to the national grid during the crop season. Coal is burned during the inter-crop season by two of these factories to provide power.

The whole island of Mauritius is serviced with electricity through overhead cables greatly due to considerable investment in infrastructure which guarantees a consistent and standard supply of power. More than 80% of electrical power is generated by thermal plants, while the remaining 20% is generated by hydroelectric power and bagasse.

Mauritius relies on imported petroleum products to meet largely its energy needs as it has no oil, natural gas or coal reserves. Hydro power, biomass, wind and solar energy are local and renewable sources of energy present in Mauritius.Â  Bagasse which is a by-product of the sugar industry is the main component of biomass and supplies around 22 % of the prime energy supply. Charcoal and fuel wood are used in negligible amount.

Hydropower plants involving a combined installed capacity of 59 MW are nearly the entire hydro potential the island possesses.Â  Moreover, Mauritius has an excellent solar regime with an average annual solar radiation value of 6 kWh/m2/day. The wind regime is very good in certain areas of the island having an annual average speed of 8.1 m/s at 30 m above the ground.

Some 900Â 000 tons of petroleum products are imported by the country, comprising of heavy fuel gasoline, oil, kerosene, diesel, LPG, and about 225 000 tons of coal yearly. 75.4 % of the primary energy requirements are obtained from the imported petroleum products and coal. Local and renewable sources, especially bagasse and hydro cover up for the remaining balance. With an eye to reduce dependency on imported energy, government policy promotes the utilisation of renewable energy.

Energy resources in Mauritius


Coal can be defined as the solid end result of decomposition of organic materials over millions of years. In fact, coal is stored solar energy. Plants take in light energy from the sun through photosynthesis, which is converted to plant matter.

After millions of years, plant and animal matter accumulate. The weight of the earth's surface slowly transforms this matter into a hard black solid. When burnt to generate electricity, fossil fuels like coal release its stored energy within a few minutes while they need millions of years to be created. Coal cannot be considered as a renewable resource since it cannot be recovered once extracted and burned.

Coal is normally burned to create steam, which is then pumped at high pressure over a turbine which rotates, and produces electricity. This method is commonly used with other fuel sources, such as biomass, oil, natural gas, geothermal, and even some solar-fueled systems.


BagasseÂ is the fibrous by product formed whenÂ sugarcaneÂ stalks are crushed to extract their juice.Â This residual matter is currently used as aÂ biofuelÂ to generate electricity and as a renewable supply in the manufacture ofÂ pulpÂ and paper products.

Around 3 tonnes of wet bagasse is produced by a sugar factory for each 10 tonnes of sugarcane crushed. The amount of bagasse produced depends on the quantity of sugarcane produced in each country as bagasse is a by-product of the cane sugar industry.

Bagasse usually has 40 to 50% of moisture content which is quite high and is not beneficial to its use as a fuel. Therefore, bagasse needs to be stored before any further processing. For electricity production, bagasse is stored under moist conditions to allow reactions in the bagasse pile to degrade residual sugars slowly.

Sugar mills frequently use bagasse as a primary fuel source to produce enough heat energy to meet all the needs of a typical sugar mill with energy to spare. Cogeneration is another use of bagasse. It is the use of a fuel source to provide heat energy used in the mill, and electricity which is in general sold on to the consumerÂ electricity grid.

Carbon dioxide (CO2)Â emissions which result from this process are equal to the amount of CO2Â absorbed by the sugarcane plant from the atmosphere during its growing phase. This makes cogeneration a greenhouse gas-neutral process.Â 

Hydro power

More or less 90 percent of the country's hydropower potential has been developed. There is currently 59 MW of hydro capacity in operation.

8 hydroelectric power stations in operation ranging in size from 900 kW to 30 MW capacities are found in the country. These include Champagne Power Station, Ferney Power Station, Le Val Power Station, Tamarind Falls Power Station, Reduit Power Station, Cascade Cecile Power Station, La Ferme Power Station and Magenta Power Station.

Before the mid eighties, hydroelectric power-stations contributed a lot to the production of electricity. In spite of running at maximum load, the stations could not deliver due to increasing electricity demand.

The government is not keen on investing in the hydroelectric sector without guarantee that it will consistently meet electrical demands. Water is now being used for city water supply and irrigation while it was formerly used to operate turbines.

Small hydropower plants have been developed by some of the country's sugar mills but it does not contribute much to the country's total electricity needs. However if several small hydropower plants are operated, the electricity produced could become considerable.

Solar energy

The sun is the world's ultimate source of energy. It supplies the earth with light, heat and radiation. The earth benefits from a steady and enormous flow of radiant energy that far surpass what is required as electricity fuel for the whole world.

Solar energy can be considered as a renewable source of electricity generation since it does not deplete any of the earth's natural resources. There are two different ways to generate electricity from the sun namely photovoltaic (PV) and solar-thermal technologies.


Timber, agriculture and food processing wastes or from fuel crops that are purposely grown or held in reserve for electricity generation is what biomass is made up of. Biomass fuel can consist of sewage sludge and animal manure also. Trees can also be a source of biomass fuels. These fuels can be considered as renewable since they can be restored. Burning crop residues, sewage or manure and all wastes can be beneficial since they are constantly being produced. These can be used to generate electricity and at the same time maintain landfill space.

One of the main advantages of using biomass technologies is that combustion can be performed at anytime to generate electricity, unlike wind and most solar technologies, which can only be used when the wind is blowing or sun is shining.

Components of a coal power plant

Â Electricity from coal

The energy stored in coal is used to generate electricity. The energy in coal is obtained from carbon which is made from ancient plant material. Combustion of the coal is what released this energy. Coal is used as the primary fuel to generate more than half of the electricity produced in the world. Electricity generated from coal is used for various purposes such as heating, cooking, transportation, lighting, communication, among others.

With the world developing so fast, there are power shortages in nearly all places whilst the need seems to be always growing. The purpose of a coal fired thermal power plant is to convert the energy available in the coal to electricity. StoredÂ energyÂ in coal is converted to usable electricity through numerous steps in a coal power plant.

Coal conversion to electricity

For the coal to burn more quickly, it is first crushed to a fine powder so as to increase the surface area. In these pulverised coal combustion (PCC) systems, the powdered coal is burnt at high temperature after being propelled into the boiler's combustion chamber. Water found in tubes lining the boiler is converted into steam by the hot gases and heat energy produced.

Figure 1: Coal power plant

High pressure steam is directed into a turbine which consists of thousands of blades which further propel the steam. The turbine shaft rotates at high speed as it is being pushed by the steam. A generator is positioned at the end of the turbine duct and electricity is generated when these are rotated. After going all the way through the turbine, the steam is returned back after being condensed to the boiler to be used once again.

The electricity produced is generated at high voltages which may rise up to 400,000 volts which is normally used for economic and efficient transmission by means of power line network. The electricity is then reduced to 100-250 volts which is safer and used in the domestic market for consumption such as our homes.

Features and functions of a typical power plant

Although all plants are different from others in terms of specific features and functions, there is still a plan to which all thermal power plants conform. A thermal power plants consists of four main circuits, namely:

Coal & Ash CircuitÂ - this circuit provides the boiler with coal for combustion uses and ensures that ash produced after the combustion process is dealt with. It also caters for the disposal and storage of coal ash with appropriate equipments.

Air & Gas CircuitÂ - air can be considered as one of the key elements of the fire triangle and is therefore essential for combustion. An adequate quantity of air needs to be supply to the boiler for coal combustion. Before being released in the atmosphere, the exhaust gases from the combustion are then used to heat the arriving air.

Feed Water & Steam CircuitÂ - this section supplies the turbines with steam that have been generated from the boiler and also cools down the outgoing steam from the turbine to have water which can be reused in the boiler.

Cooling Water CircuitÂ - this fraction of the thermal power plant manages the cooling water necessary for the system. A considerable amount of water is needed to cool the outgoing steam from the boiler and is therefore either taken from a nearby water source, or is done by evaporation if the amount of cooling water on hand is limited.

Electricity delivery

Electricity is emitted by electricity-generating plants using a transformer. The transformer increases the voltage of the electricity depending on the amount needed and the distance to which it must be distributed. The voltages often rise up to 500,000 volts at this particular point. Transmission lines carry this electricity to substation transformers. The voltage is reduced by these transformers for use. The electricity then travels along distribution lines from substation transformers either below or above the ground to cities and towns. For use at homes and businesses, the voltage is brought down again to around 120 to 140 volts. It is an immediate delivery process. Electricity is delivered as soon as a switch is flipped to turn on a light.

Coal fly ash

Coal is mainly made up of organic matter. However, it is the inorganic matter in coal, namely minerals and trace elements that have been named as possible sources of environmental, technological and especially health problems. Some of these elements are naturally radioactive including uranium, thorium, and their numerous decay products. Issues have been raised regarding potential hazards from radiation even though these elements are less toxic than other constituents like selenium, arsenic or mercury.

Source and descriptionÂ Â 

If dispersed in air and water or included in commercial products that contain fly ash, these elements from coal and fly ash may come in contact with the general public.Â Coal ash is the mineral deposit that is produced as a result of coal combustion to generate electricity.

Fly ash is the finest of coal ash particles which make up 85% - 90% of the overall ash. It is known as "fly" ash since it is carried away by exhaust gases from the combustion chamber. Coal fly ash is the dust produced from mineral matter found in coal. It consists of noncombustible substance plus small quantities of leftover carbon from incomplete combustion. Fly ash is generally light tan in colour that gives it a consistency somewhat like talcum powder.

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Composition of fly ash

The physical and chemical characteristics of fly ash vary considerably depending on the coal composition and the conditions at the coal power plant. The most common elements as well as toxic ones are found in trace quantities which may at times demands precautionary actions to be taken concerning the environment. Moreover, radioactive elements are present in small amounts in the ash, but their concentration is quite larger as compared to their concentrations in the soil and rocks. The dark colour results from unburned carbon deposit.

Characteristics of fly ash

The physical and chemical properties of ash make it a valuable raw material to be used in several applications. The characteristics of fly ash from a single source may be uniform, or quite variable, depending on factors such as the source of the coal, age of plant, operating conditions, degree of coal pulverisation, ash collection and processing methods. The most significant factor of ash produced remains the coal source (Cook 1983:51).

It is therefore evident that the percent composition of fly ash particles will slightly differ because of the coal source. Elemental analysis of the fly ash shows that the main components are silicon, aluminium, iron and calcium.

Uses and applications of coal fly ash

Fly ash has been used for over 50 years in a wide range of applications. However, the two most common uses of coal fly ash remains for construction and agricultural purposes.

Construction uses of fly ash

Fly ash can be either cementitious or pozzolanic. A material which hardens when mixed with water is known to be cementitious while a material which hardens with water but only after activation with an alkaline substance such as lime is referred to as pozzolanic. These properties are what make fly ashes useful as a replacement for cement in concrete and in other building purposes.Â 

Fly ash can therefore be used to substitute or complement cement in concrete. Among the most important environmental benefits of using fly ash is that it considerably reduces greenhouse gas (GHG). Each tonne of fly ash used with a tonne of Portland cement, roughly one tonne of carbon dioxide is kept from crossing the atmosphere.

The use of coal combustion products (CCP) diminishes GHG emissions, decreases need for landfill space, and remove the call for using primary raw materials. A concrete which is stronger and more durable is produced from fly ash. It is resistant to corrosion, sulphates and other types of chemicals.

Agricultural uses of fly ash

Fly ash has similar physical and chemical properties to those of soil. It can be used directly as a soil amendment, or in land reclamation, with organic matter, lime or gypsum, in composts, or made into granulated materials or potassium silicate fertilisers.

Fly ash improves the physical properties of the soil, increasing moisture retention in poor soils and aeration. It provides the micronutrients for plant growth, but lacks potassium and only supplies a limited amount of nitrogen. Fly ash has been applied successfully in specific agricultural projects in many countries, such as Australia, Germany, India, Japan, South Africa, the UK and the USA. Fly ash composted with earthworms improved yield so that expensive chemical fertiliser applications could be reduced. However, the source and quality of fly ash needs to be matched with the soil being treated, the crop being grown as well as the local climate.

Another agricultural use of fly ash is as pesticide due to the fine powder form. Arsenic, boron and aluminium present may cause toxicity although they are usually within regulated limit values.

Benefits of using coal fly ash

The environmental availability, great quantity, and economy of CCPs transform into benefits for organisations. Industries gain a lot as they do not have to forgo product quality and at the same time they save cost. The properties of CCPs improve the product in many applications where they are used.

Coals ashes improve the strength of materials in engineering construction materials while at the same time reduce the cost. Gypsum-rich products can provide plant nutrients and improve the health of depleted soils if used for agricultural purposes. The properties of CCPs can be used in waste stabilization to halt hazardous nuclear and toxic metal wastes for harmless and useful disposal.

Health hazards of exposure to coal fly ash

The processing of coal fly ash can expose employees of coal-fired power stations as well as people living nearby to coal fly ash dust. Extensive researches programmes are carried out in order to map such exposure and its effects.

Routes of entry

There are three main routes through which airborne particulates can enter the body and these are described below.


Normally, this route of entry is not always common in the world environment. This may occur sometimes due to some people who may unknowingly eat or drink dangerous chemicals. This may also happen where there is a lack in personal hygiene in the work environment. During such cases, employees will ingest harmful substances since they did not wash their hands after working in a contaminated area.

Some toxic dust that is insoluble in digestive fluids will be eliminated directly through the intestinal tract when swallowed with food or saliva. On the other hand, toxic materials in dust that are readily soluble in the digestive fluids can be absorbed into the blood from the digestive system (Plog, 1996:21,125).

Skin absorption

Cuts or abrasions can cause absorption to occur quite rapidly through the skin. If the skin is intact, it acts as a proof against most inputs. However there exist certain substances and microorganisms capable of passing through the intact skin into inner tissues or even into the blood stream, without actually causing any change in the skin itself. There are numerous compounds that are easily absorbed through the intact skin. Some substances are absorbed through hair follicles while others like organic lead compounds dissolve in the fats and oils of the skin.


Major causes of deaths and illnesses associated with toxic substances are inhalation of substances in the form of dust, fume, gas, vapour or mist (Stranks, 1997:241). Industrial exposures to chemicals mostly occur through inhalation. Nearly all airborne materials can be inhaled.

Inhalation causes toxic material to enter the lungs, get into the blood stream, and move to other parts of the body. The amount of toxic compound absorbed by way of the respiratory pathways depends on its concentration in the air, the duration of exposure and the pulmonary ventilation volumes (Plog, 1996:21,125).

Target organs

When dangerous substances such as fly ash dust are taken into the body, they deposited in and act upon a particular body organ and/or a particular body system. The lungs, bladder, skin and brain are the most common organs which get affected whilst the most common target systems are the central nervous system, circulatory system, reproductive system and the urine-genital system (Stranks, 1997:241).

Toxic substances present in coal ash

Toxic substances found in coal ash can severely affect the human body and the environment. Many people are still not aware of how toxic coal ash is, or how much of it exists. Coal ash commonly contains some of the earth's deadliest toxics: arsenic, lead, mercury, cadmium, chromium and selenium.


Lead is considered to be among the four most toxic metals for human health. Intake of food, water and air are medium through which it can enter the human body. Till now, lead has no necessary use in the body, it can only harm after uptake from water, food or air. It can be the source for several negative effects, such as disturbance in the formation of haemoglobin causing anaemia, increase in blood pressure, kidney problems, disorders in the nervous systems, men infertility.


Arsenic is considered as one of the most lethal elements that exist and can be found in coal fly ash. Despite their toxic effect, the earth naturally contains small amounts of arsenic and exposes humans to arsenic through water, air and food. Exposure to arsenic can pose various health problems, such as pains in the stomach and intestines, reduction in the amount of red and white blood cells produced and changes in the skin. The uptake of significant amounts of arsenic can increase the chances for cancers to develop and lastly arsenic can also damage the human DNA.


The quantity of mercury in the environment has increased due to human activities in a number of ways, namely through a variety of combustion and industrial processes like coal-fired power generation, metal mining and waste incineration. Mercury present in fly ash primarily causes various health effects when breathed in as a vapour as it gets absorbed through the lungs. High exposures may damage the gastrointestinal tract, the nervous system, the kidneys, and the respiratory failure which may result in death.

Action of toxic substances

The toxic action of a substance can be subjectively divided into acute and chronic effects (Plog, 1996:129).

Acute effect

Acute effects involve short-term high concentrations and immediate results of some kind. Occupational exposures are frequently related to an accident.

Chronic effect

Chronic effects on the other hands develop slowly with ultimate development of a disease. The term chronic exposure refers to exposure sustained for a prolonged period usually long years.

Neoplasm and reproductive toxicity caused by exposure to coal dust


A mutagen is an agent that affects the genetic composition of the exposed organism. It might cause cancer, birth defects or unwanted effects in later generations. Mutations normally show up until the next generation at the earliest, and may not appear for several generations (Plog, 1996:135).


Metals such as lead and mercury have been identified as human teratogens. A teratogen can affect a developing fetus. Even if a fetus is protected from some toxic chemicals because of the placenta that prevents them from entering the fetal bloodstream, toxic metals such as lead can easily cross the placenta.


Carcinogen refers to agent that can generate or accelerate the development of malignant or potentially malignant tumors or proliferation of cells in humans following a reasonable exposure (Plog, 1996:134).

Cancer of the respiratory tract, usually the lungs are often caused by inorganic salts of metals such as chromium, and to a lesser extent nickel compounds. Other metals such as beryllium and cobalt are suspect carcinogens.

Risk assessment

Risk assessment is "a systematic process for describing and qualifying the risks associated with hazardous substances, actions or events." (Covello et al.)

It is the process where the safety and health risks to workers' from hazards at the workplace are being evaluated. Risk assessment can be used as a tool to aid for decision making. Risk assessment can be said to be an analysis of any given task in an organization. It consists of identifying the features that could be harmful, quantifying the severity and likelihood of the harm and implementing control measures that will lessen the level or probability of the harm.

The European approach to put off occupational accidents and ill health is through carrying out risk assessment. The law says that employees have to be protected from harm which arises from a failure to take control actions. The law does not expect you to eliminate all risk, but you are required to protect people as far as is 'reasonably practicable'.

Importance of risk assessment

Risk assessment is an active process that allows enterprises and organisations to establish a proactive policy for managing workplace risks.

Risk assessment can be considered as one of the most essential aspects of good health and safety practice. Effective risk assessment will allow businesses to spot the areas of the organisation where employees are most apparently at risk, and set up strategies to mitigate these risks. Hence, risk assessment is an important legal obligation. Moreover, businesses will benefit from having minimized the potential risks to their employees 'as far as is reasonably practicable', as the law states that an unprotected labor force is likely to be costly resulting from lost output, increased insurance premiums, or court costs.

Legislation on risk assessment

In Mauritius, management has a legal responsibility under section 5 of the Occupational Safety and Health Act 2005 (OSHA 2005) to ensure so far as is reasonably practicable the safety, health and welfare of all his employees at the workplace. Furthermore, there is a general requirement in section 10-11 of the OSHA 2005 for the employer to carry out risk assessments.

Risk assessment

Every employer shall make a proper and adequate assessment of-

the dangers of exposure to the safety and health of his employees whilst they are at work: and

the risk to the safety and health of persons who do not work for him but who perform a job related to his enterprise,

to spot the control measures he needs to abide with the laws for the relevant provisions.

Purpose of risk assessment

In general, the objectives in a risk assessment are to identify potential system failure and exposure to any harm present. This process will facilitate the designs of techniques that will help reduce the probability of failure. It will also provide as far as possible complete information set so that the best decisions can be taken concerning potentially hazardous situation.

The idea of a risk assessment is to allow the employer to take the required control measures to provide better safety and health protection to his workers. These actions comprise the prevention of work-related risks, proper information provided to workers concerning risks involved in a given task, and also by providing appropriate training to workers.

Indeed as Whyte and Burton (1980) stated, a major objective of the risk assessment process is to develop risk management decisions that are more systematic, more comprehensive, more accountable, and more self-aware of appropriate programs that has often been the case in the past.

Risk assessment does not only provides information on the nature and magnitude of potential health and environment risks associated, but provides a basis for judging needs for any type of control measures according to Asante-Duah (1998).

Five steps risk assessment process

A risk assessment helps you focus on the risks which are the most likely to cause harm at the workplace. It simply means simple and useful measures to ensure your most precious asset which is normally the workforce is protected. A risk assessment can be done in different ways in diverse situations as there is no single 'right' way. A simple five-step approach including elements of risk management should work well for almost all businesses. It is believed that the five-step approach is the most straightforward for most organisations.

Step 1. Identification of hazards and those at risk

Â The first step consists of identifying stuffs at work that can cause harm, and employees who may be exposed to them. This can be done by looking at the organisation's accident and ill-health records, or by seeking information from other sources such as instruction manuals or data sheets, occupational safety and health websites, trade associations or trade unions, legal regulations and technical standards.

Step 2. Evaluating and prioritising risksÂ 

Once the hazards have been identified, the existing risks should be estimated in terms of severity and probability of occurrence, and prioritised in order of importance. The risk arising from each hazard has to be evaluated. This is done by considering the probability that a hazard will cause harm (e.g. whether it is impossible, possible but not very likely, possible, or inevitable over a point in time), and how severe that harm is likely to be (e.g. resulting in trivial damage, a non-injury incident, a minor injury, a serious injury, a fatality, or a multiple-fatality).

Step 3. Deciding on preventive action

This step spots the appropriate actions to remove or manage the risks by establishing preventive and protective measures. Some aspects that need to be considered are to determine whether the task or job is necessary, implement different work processes which will adapt the work with the individual. Dangerous machines could be substituted with less dangerous ones, better organization of work, better working conditions and appropriate instructions to workers could be very effective control measures which could be implemented.

Step 4. Taking action

When the most suitable control measures have been found, the next step is to implement them successfully.Â Effective implementation consist of developing a plan which specifies the measures to be put into practice, the means available in time, expenses and resources, what is to be done, by whom, when the proceedings have to end, and a reviewing date for control measures.


Step 5. Monitoring and reviewing

Risk assessment should not be an activity which is carried out once-and-for-all. It should be evaluated at regular intervals to make sure that it is up to date for a number of reasons. These includes the degree of change in the work activity, changes which might alter the way employees see hazards in the workplace, the preventive and protective measures already present being no longer appropriate, and as a result of the conclusion of an accident.

Records keeping of risk assessment

The OSHA 2005 states that an employer who employs more than 5 persons shall record in a register the significant findings of any assessment carried out and also any group of employees identified as being especially at risk. Such records can be used as a foundation for information to be transmitted to the personnel concerned, for examination to evaluate whether necessary precautions have been initiated, for facts to be generated for supervisory authorities, and for any revision if circumstances changes.


Risk assessment tools

There are various tools and methodologies used for risk assessment which are available to assist organisations in assessing the safety and health risks to their employees. The method used have to be chosen depending on the work conditions, such as the number of staffs, the type of works being done and equipment used, and the particular characteristics of the workplace.

Risk estimation

It is frequently considered that risk can be calculated using the following simple formula:

Risk = probability * consequences

This leads people to assign numerical values to probability and to consequences and so calculate a numerical value of risk. These values can be on a predetermined scale ranging from 1 to 5, or 1 to 10. These give risk values which may rise up to 100 (10*10). The risk level is therefore determined through a scale where risk can be either intolerable, alarp, or acceptable.

There are several drawbacks associated with this method used for risk estimation and evaluation of risks. It appears to miss out vital components such as the exposure time to the hazard and the interpretation of terms such as frequent, probable, or improbable, etc.

Risk calculator

The risk calculator was developed by H. Raafat as an instrument to identify the risks in order to find the risk levels considered as intolerable. The calculator also has the ability to compare several types of risks on the same scale, namely individual, economic, societal and environment risks. It is important to note that the risk calculator main objective is to provide a ranking of risks rather than criteria for risk tolerability.

The basic elements in calculating the order of magnitude of risk are the probability level that a hazard is likely to occur, the frequency of occurrence and the exposure time to the hazard, and the consequences or potential severity of injury.

By connecting the appropriate points on each scale and using the tie line in the middle of the calculator, it is possible to determine the level of risk involved. The risk level can be divided into three main categories where high risk indicates that the risk level is unacceptable, substantial risk indicating that the level of risk should be reduced and low risk where the level can broadly be accepted.

Checklists are the most frequently used risk assessment tool and are useful to identify hazards. Some other examples of risk assessment tools questionnaires, guidance documents, handbooks and interactive tools or software.

Objective of report

This study is focused on gathering information regarding the health hazards of exposure to fly ash dust and to cover aspects of importance that would best address the concerns raised by the coal fired power station personnel to determine a solution for this problem. The employees are exposed to a high level of dust that causes an occupational hygiene risk while training guidelines and safety knowledge are inadequate to attend to the training of workers.

The aim of this study is not to reproduce the results of any previous study on the health hazards of fly ash dust, but to come out with or disclose additional information that will describe the hazards or risks of exposure to fly ash dust. The lack of sufficient scientific knowledge and evidence by employees and employers on the dangers to health associated with exposure to fly ash dust are factors which initiated the study.

By observing work practices, adherence to personal hygiene whilst performing the task, as well as the evaluation of training of workers at the power station, the appropriate control measures will be determined. This will also help to evaluate the level of occupational hygiene, safety knowledge and training of exposed employees. Finally recommendations will be made for the development of training guidelines for the control of personal exposure to fly ash dust.