|Year : 2017 | Volume
| Issue : 2 | Page : 56-76
Hazard identification, risk assessment, and control measures as an effective tool of occupational health assessment of hazardous process in an iron ore pelletizing industry
BK Rout1, BK Sikdar2
1 Assistant General Manager (Medical), Jindal Stainless limited, Jaipur, Rajasthan, India
2 Deputy Chief Inspector of Factories (Med) and Certifying Surgeon, West Bengal, India
|Date of Web Publication||13-Feb-2018|
B K Rout
J 508, Trident Galaxy, Kalinga Vihar Phase 3, Paikrapur, Bhubaneswar - 752 054, Khurda, Orissa
Source of Support: None, Conflict of Interest: None
Background: With the growing numbers of iron ore pelletization industries in India, various impacts on environment and health in relation to the workplace will rise. Therefore, understanding the hazardous process is crucial in the development of effective control measures. Hazard Identification, Risk Assessment, and Control measures (HIRAC) acts as an effective tool of Occupational Health Assessment. Objective: The aim of the study was to identify all the possible hazards at different workplaces of an iron ore pelletizing industry, to conduct an occupational health risk assessment, to calculate the risk rating based on the risk matrix, and to compare the risk rating before and after the control measures. Materials and Methods: The research was a cross-sectional study done from March to December 2015 in an iron ore pelletizing industry located in Odisha, India. Data from the survey were collected by inspecting the workplace, responses of employees regarding possible hazards in their workplace, reviewing department procedure manual, work instructions, standard operating procedure, previous incident reports, material safety data sheet, first aid/injury register, and health record of employees. Results: A total of 116 hazards were identified. Results of the paired-sample's t-test showed that mean risk rating differs before taking control measures (M = 9.13, SD = 5.99) and after taking control measures (M = 2.80, SD = 1.38) at the 0.0001 level of significance (t = 12.6428, df = 115, N = 116, P < 0.0001, 95% CI for mean difference 5.34 to 7.32). On an average, risk reduction was about 6.33 points lower after taking control measures. Conclusion: The hazards having high-risk rating and above were reduced to a level considered As Low as Reasonably Practicable (ALARP) when the control measures were applied, thereby reducing the occurrence of injury or disease in the workplace.
Keywords: Control measures, hazard identification, hazardous process, iron ore pelletizing industry, risk assessment
|How to cite this article:|
Rout B K, Sikdar B K. Hazard identification, risk assessment, and control measures as an effective tool of occupational health assessment of hazardous process in an iron ore pelletizing industry. Indian J Occup Environ Med 2017;21:56-76
|How to cite this URL:|
Rout B K, Sikdar B K. Hazard identification, risk assessment, and control measures as an effective tool of occupational health assessment of hazardous process in an iron ore pelletizing industry. Indian J Occup Environ Med [serial online] 2017 [cited 2019 Jul 18];21:56-76. Available from: http://www.ijoem.com/text.asp?2017/21/2/56/225344
| Introduction|| |
India has the fourth largest iron ore reserves in the world after Russia, Brazil, and Australia. As per the survey conducted by the Indian Bureau of Mines (IBM) in April 2000, India had 9919 million tonnes of recoverable reserves of haematite and 3546 million tonnes of magnetite.
As good quality iron ore deposits are depleting very fast, beneficiation technologies have to be adopted to meet iron ore demand. Agglomeration technologies such as pelletization/sintering have to be added to steel plant so that concentrates can be used as feed material.
Pelletization plants beneficiate fines and transform the unusable low grade fines into an easily consumable feed for blast furnaces. The present production capacity of pelletization in eastern region is 28.7 MMT, which will increase to 40.7 MMT in the coming time after commissioning of about 9 number of units, which are at various stages of commissioning. With the growing numbers of pelletization plants, various impacts on environment and health will rise.
A critical part of any Occupational Health and Safety program is the identification, assessment, elimination and/or the control of hazards in the workplace. Risk assessment is the process of evaluation of the risks arising from a hazard, taking into account the adequacy of any existing controls and deciding whether or not the risks is acceptable. It is impossible to eliminate all hazards, so the goal is to eliminate and/or control the hazards with critical and high potential risk to the lowest reasonable risk level so as to protect workers from harm.
Section 2 (cb) of the Indian Factories Act, 1948, defines hazardous process as follows:
“Hazardous process” means any process or activity in relation to an industry specified in the First Schedule where, unless special care is taken, raw materials used therein or the intermediate or finished products, by-products, wastes, or effluents thereof would:
- Cause material impairment to the health of the persons engaged in or connected therewith, or
- Result in the pollution of the general environment.
Hazard means a source or a situation with a potential for harm in terms of human injury or ill health, damage to property, damage to the environment, or a combination of these.
Hazard identification means the identification of undesired events that lead to the materialization of the hazard and the mechanism by which those undesired events could occur.
Risk is, at minimum, a two-dimensional concept involving (1) the possibility of an adverse outcome, and (2) uncertainty over the occurrence, timing, or magnitude of that adverse outcome. If either attribute is absent, then there is no risk.
Risk assessment is a systematic process for describing and quantifying the risks associated with hazardous substances, processes, actions, or events.
Risk assessment method can be defined as any self-contained systematic procedure conducted as part of a risk assessment – that is, any procedure that can be used to help generate a probability distribution for health or environmental consequences.
Hazard Identification Risk Assessment (HIRA) is a process of defining and describing hazards by characterizing their probability, frequency, and severity and evaluating adverse consequences, including potential losses and injuries. A risk assessment that provides the factual basis for activities proposed in the strategy to reduce losses from identified hazards. The ISO Risk Management Principles and Guidelines standardize risk assessment in four parts: risk identification, risk analysis, risk evaluation, and risk treatment. The first step — risk identification — is achieved by identifying all hazards and their subsequent consequences. Local risk assessments must provide sufficient information to enable the jurisdiction to identify and prioritize appropriate mitigation actions to reduce losses from identified hazards.
Hazard control means the process of implementing measures to reduce the risk associated with a hazard.
Scope of the study
The occupational health risk assessment shall address the following:
- The hazards of the process involved in different activities
- Semi-quantitative evaluation of the possible health and safety effects of failure of controls
- Engineering and administrative controls applicable to the hazards and their interrelationships, such as appropriate application of detection methodologies to provide early warning of release.
| Materials and Methods|| |
The study was cross-sectional in design and involved semi-quantitative methods of data collection. Primary data was obtained by inspecting the work place, interacting with employees regarding the possibility of hazards, reviewing the department procedure manual, work instructions, standard operating procedure, and incident report, whereas secondary data was collected using Material Safety Data Sheet (MSDS), first aid/injury register, health record of employees, journals, and literatures.
The study was carried out in a 4-m tonne iron ore pelletizing industry located in Odisha, India from March to December 2015. The pellet plant used travelling grate technology to convert low grade fines into value-added pellets.
The slurry was received at the pellet plant from the beneficiation plant through a 220-km pipe line. It was stored in the holding tanks before being fed through pressure filters and mixed with the additives. The purpose of the additives - limestone, bentonite, coke, and anthracite – was to improve the physical and metallurgical properties of the pellets during processing and in final use. A disc pelletizer was then used to ball the mixture into “green balls” about the size of a marble.
A roller screening mechanism was used to remove any undersized material before the green balls enter the final stage of production, the induration furnace. The induration process used travelling grate technology and a series of updrafts and downdrafts to dry and gradually heat the green balls to remove moisture before entering the combustion zone where they were first preheated to minimize thermal shock, then fired, and ultimately cooled in various sections of the furnace. After screening out oversized and undersized pellets, the final product – which had the required properties for charging a blast furnace and ready to withstand handling and transportation – were transferred by conveyor to a stockpile.
The different steps of methodology are mentioned in the [Figure 1].
|Figure 1: Flow chart of methodology of hazard identification, risk assessment, and control measures|
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Classification of work activities
Identification of hazard
All the work activities pertaining to various departments were minutely examined to identify all the possible hazards inherent to the nature of work or work environment [Table 1]. The following methods were used to identify the hazards in the workplace:
- Walking around the workplace to inspect what is in the general area
- Employee participation by interacting with them regarding their work place, working hours, and the possible hazards they noticed [Annexure 1][Additional file 1]
- Reviewing of Department Procedure Manual (DPM), Work Instruction, and Standard Operating Procedure (SOP) and comparing it with the regular practice
- Reviewing previous Incident Reports
- Reviewing Material Safety Data Sheet (MSDS)
- Reviewing first aid/injury records
- Reviewing health records of employees.
Identification of risk
After all the possible hazards were identified, the occupational health risk that could be associated with the hazard was identified by studying previous incident reports, MSDS, first aid/injury records, and health records of the employees.
Assessment of risk
Risk assessment was done using semi quantitative method  based on two key factors [Table 2]:
- The likelihood that the injury (or illness) may actually occur
- The severity of the injury (or illness) resulting from the hazard.
Control of risk
Risk rating can prioritize hazards with the highest potential to cause an injury so that they can be eliminated first [Table 3] and [Table 4].
The following steps were taken for the control of risk:
- Quick attention to critical or high-risk hazards
- Effective temporary solutions until permanent fixes were applied
- Long-term solutions for those risks which can cause long-term illness
- Long-term solutions for those risks with the worst consequences
- Training of workers on the risks, which continue to remain and its control measures
- Regular monitoring to check whether control measures are intact or not.
Documentation of procedure
Documenting the process helps to ensure that the identified risk control measures are implemented in the way they were intended. It will also assist in managing other hazards and risks that may be in some way similar to ones already identified. Adequate record keeping of the risk management process should show that the process has been conducted properly. This information should include:
- Hazards identified
- Assessment of the risks associated with those hazards
- Decision on control measures to manage exposure to the risks
- How and when the control measures are implemented
- Evidence of monitoring and reviewing of the effectiveness of the controls.
Monitoring and review
It involves reassessment of the risk to see whether there is a reduction of risk rating from critical and high risk to a level considered As Low as Reasonably Practicable (ALARP).
| Results|| |
In this plant, 116 hazards were identified and their analysis was performed. They have been classified into five major categories [Figure 2].
|Figure 2: Frequency of different hazards in an iron ore pelletizing industry|
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- Fire and explosion
- Dust, chemicals, and toxic substances
The major hazards, risk assessment, and the reduction of risk after taking appropriate control measures are tabulated below [Table 5] and [Figure 3].
|Figure 3: Reduction of extreme and high risk rating to acceptable risk rating after control measures|
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|Table 5: Hazard identification, occupational health risk assessment before and after control measures|
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Statistical analysis involves the calculation of the mean of a set of values in a sample used for observational study. Hypothesis testing is used to make an inference about a population that is under study. The null hypothesis is the assumption that the mean will be equal to zero. The paired t-test is a type of hypothesis testing that is used when two sets of data are being observed. The data in a paired t-test are dependent, because each value in the first sample is paired with a value in the second sample. The parameter used to make the inference is the difference of the means of both data sets.
Statistical analysis was done using GraphPad's website. A value of P < 0.05 was considered significant [Table 6].
Results of the paired-samples t-test show that mean risk rating differs before taking control measures (M = 9.13, SD = 5.99) and after taking control measures (M = 2.80, SD = 1.38) at the 0.0001 level of significance (t = 12.6428, df = 115, n = 116, P < .0001, 95% CI for mean difference 5.34 to 7.32). On an average, risk reduction was about 6.33 points lower after taking control measures.
| Discussion|| |
In this cross-sectional study, it was found out that by applying control measures, hazards having high risk rating and above was reduced to a level considered ALARP. The findings suggest that Hazard Identification, Risk Assessment, and Control measures (HIRAC) study on a routine basis can serve as a tool to reduce occurrence of injury or disease in any manufacturing industries.
Health, Safety, and Environment (HSE) department is the core pillar of any manufacturing industry. Other departments such as manufacturing, engineering services, commercial, and human resources are strongly linked with the HSE department [Figure 4].
|Figure 4: Integrity of health safety and environment (HSE) department with other departments|
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HSE department has a lot of common functions and they play a great role in identifying hazards, risk assessment studies, and their control measures through monthly Safety Committee meeting.
In tough economic times, it is important to remember that poor workplace safety and health costs money. What's more, case studies show that good Occupational Safety and Health management in a business is linked to improved performance and profitability.
The various steps of occupational health assessment of hazardous process in an iron ore pelletizing industry are as follows:
The concentrate slurry is received at pellet plant and stored in slurry tanks [Figure 5]. The concentrate slurry is fed to the filtration process where it is de-watered by pressure filters. The product comes out is called filter cake (moisture 9%), which is stored in bin for further process of mixing. The filtrate water so generated is sent to process reservoirs via thickener for storage and internal plant consumption.
Pellet plant is facilitated with additives grinding unit as the process of pelletization requires binder and additives. Bentonite is used as a binder for proper balling of the filter cake particles in to spherical shaped balls with certain compression strength. The bentonite is stored and ground in a Vertical mill by dry grinding process to desired fineness (−200 mesh, 80%). The powdered bentonite is stored for further mixing process. Limestone is used as a fluxing agent and to get strength to the pellet by heat hardening. Coke dust is used as a compensatory fuel and to improve physical strength of the pellets by uniform firing of each pellet up to the core. Both limestone and coke are ground in a definite lime to coke ratio in a ball mill by dry grinding process. The product is lime + coke powder mix of desired fineness (−200 mesh, 80%) is stored for subsequent mixing process.
In mixing and baling building, bentonite, lime + coke mix are added to the concentrate filter cake at a definite rate of addition and is thoroughly mixed in a vertical mixer. The so-mixed concentrate is called mixed material, which is fed to a rotating inclined disc pelletizer. Fine ore particles are agglomerated in to spherical-shaped balls due to the rotating action of the disc. The so-formed balls are called green balls which are further screened and fed to an induration machine.
In induration building, the green balls are fed to the induration machine which forms endless chain of pallets, are slowly brought through different zones of the induration furnace by the horizontal movement of the pallets. These green balls are subjected to drying (280–340°C), preheating (350–900°C), firing (900–1330°C), and cooling (1330–100°C) in the induration furnace where pellets are in directly heated in a controlled manner by circulation of hot gases with the help of process fans. Heat energy is supplied by oil fired burners. LSHS/FO is used as fuel and source of heat energy, which is stored and pumped to burners. Critical parts of the induration furnace are cooled by water circulation. The fired and cooled pellets with good physical strength is conveyed and stored in pellet stock pile. The pellets are dispatched to the customers as a feed to blast furnace and/or Direct Reduced Iron production.
Material safety data sheet
A Material Safety Data Sheet (MSDS) provides basic information on a material or chemical product. It contains information on the properties and potential hazards of the material, how to use it safely, and what to do if there is an emergency.
The MSDS is an essential starting point for the development of a complete health and safety program for the material.
MSDS deals with the following:
- Chemical product and company identification
- Composition/Information on ingredients
- Hazards identification
- First aid measures
- Fire-fighting measures
- Accidental release measures
- Handling and storage
- Exposure controls/Personal protection
- Physical and chemical properties
- Stability and reactivity
- Toxicological information
- Ecological information
- Disposal considerations
- Transport information
- Regulatory information
- Other information.
The following MSDS were collected to study the hazardous process and its control measures in the iron ore pelletizing industries:
- Material Safety Data Sheet (MSDS) Iron ore; Cliffs Natural Resources 
- Material Safety Data Sheet (MSDS) Bentonite; Sciencelab.com, Inc 
- Material Safety Data Sheet (MSDS) Lime 
- Material Safety Data Sheet (MSDS) Furnace Oil.
- Fire and explosion
- Fugitive dusts
- Particulate matter
- Iron Oxide, Silica, Crystalline Silica as Quartz, Crystalline Silica as Cristobalite, Al2O3, CaO, MgO.
Metals – IronChemicals – acid, alkaliToxic gases
- Fumes (sulphur dioxide, oxides of nitrogen).
- Snake bite
Risk assessment can be done in three ways:
However, semi-quantitative risk assessments are currently widely used to overcome some of the shortcomings associated with qualitative approaches.
Semi-quantitative risk assessment takes the qualitative approach a step further by attributing values or multipliers to the likelihood and consequence groupings. It may also involve multiplication of frequency levels.
All risks cannot be eliminated. Urgent action is required for risks assessed as critical or high which may include instructions for immediate cessation of the work and/or isolation of the hazard until permanent measures can be implemented. Documented control plans with responsibilities and completion dates need to be developed for moderate risks.
Risk that is acceptable to regulatory agency and to the public is called acceptable risk. There are no formally recognized regulatory criteria for risk to personnel in the mining industry. Individual organizations have developed criteria for employee risk and the concepts originally arising from chemical process industries and oil and gas industries.
Because of the uncertainties linked with probabilistic risk analysis used for quantification of the risk levels the general guiding principle is that the risk be reduced to a level considered ALARP.
The aim of implementation of prevention measures is to reduce the likelihood of work accident or occupational disease occurrence. The measures used are as follows:
- Engineering control of risks [Figure 6]
- Remove – during the workspace designing phase, any equipment not meeting the occupational health standards should not be used
- Reduce – levels of hazardous substances can be reduced by proper ventilation through exhaust fans
- Replace – high-risk equipment or substances should be replaced by low risk ones.
Administrative control [Figure 6]
- Training of employees – Workers must know the risks they are exposed to, the harm they might cause, and precautions that could prevent these harmful effects
- Work instructions for every activity.
- Envelope the hazard 
Enclose or isolate the risk through the use of guards, protection of machinery parts etc
- Eliminate human interface
Use of physical barriers such as acoustic, thermal, electrical, etc.
- Envelope the individual
Use of Personal Protective Equipment (PPE) as shown in [Figure 6] to protect the worker from the residual risk. Workers must be trained regarding the selection and use of PPE.
When prevention and protective measures fail, a work accident or an occupational disease could happen. The company needs to be prepared (emergency preparedness) and to have mitigation measures implemented. The aim of mitigation measures is to reduce the severity of any damage to facilities and harm to employees and public.
Environmental monitoring and measures
There are three main objectives of assessment of exposure:
- To determine the level of exposure of workers to harmful agents,
- To assess the need for control measures, and
- To ensure the efficiency of control measures in use.
The list of air pollution control measures are shown in [Table 7].
Gas flow through stack is done by two fans 42 and 32 connected to ESP. The ESP 42 and ESP 32 are designed to blow 400,000 m 3/h and 1400,000 m 3/h of air, respectively.
The main raw material for the pellet plant is iron ore, which comes as slurry from the beneficiation plant through the pipe line. Hence, there are no fugitive emissions in raw materials handling area.
Water sprinkling is done by the water tanker on the roads and work zone areas to minimize the fugitive emissions. Fixed water sprinklers are installed in product yard area and product conveyer area.
In product area (HLSB), wet scrubbers are used to minimize particulate matter emissions and water sprinkling is done to decrease fugitive emissions.
Despite all the control measures, continuous monitoring of suspended particles is essential to ensure that it is below the permissible exposure limit.
The waste water from iron ore slurry is separated through filtration system and treated in the thickener. In the thickener, all de-dusting/scrubber return water is passed and the underflow is reused in the process. The pellet plant has a goal to achieve zero discharge norms with a comprehensive water and waste water management.
The iron ore dust collected by ESP is recycled into the thickener for its reuse in the process. Any fugitive dust generated is extracted, collected through bag filters, scrubbers, and reused in the process. Thus, no solid waste is generated.
Continuous monitoring of high noise area is done by sound meter to ensure that it is within the permissible exposure limit. Low noise generating equipments are used in the pellet plant. The equipment producing high noise are surrounded by baffles and covered with noise-absorbing material. Workers are provided with personal protective equipment to protect from noise (like ear muffs, ear plugs).
Trees are important sinks for air pollutants and absorb the noise. They enhance the green cover, improve the ecology and aesthetics and affect the local micrometeorology. Trees also have major long-term impacts on soil quality and the ground water table. A total of 19,525 trees were planted in the plant premises on an area of 12.193 Ha.
Proper housekeeping is an essential part of sound environmental management, which keeps the industry free from dusts.
Health examinations are designed to ensure that the worker is fit for employment and that he remains in that state of fitness throughout his period of employment. Any deviation from good health must be detected early and managed appropriately. Health examinations of workers frequently reveal the existence of health hazards in workplace, thus necessitating environmental evaluation and control.
Preplacement health examination (baseline records)
This examination is carried out before employment of a worker in the workplace with potential health hazards. This helps in obtaining the baseline data. It also enables the management to place workers in jobs suited to their capacities and limitations. It includes physical examination of the various organs of the body, blood and urine analysis, radiographic examination, eye examination, audiometry, and spirometry.
Periodic health examination
This examination is carried out at regular intervals after the initial examination. Emphasis is given on exposure. Periodicity depends on the nature and extent of the risk involved.
Workplace Injury and Illness Trend Analysis Program strives to identify unhealthy behaviors or hazardous conditions by tracking work-related injuries and illnesses. This information is used to target occupational health and safety education activities to prevent or reduce future employee work-related injuries and illnesses. Workplace Injury and Illness Trend Analysis includes the following:
- Tracking and monitoring workplace injuries and illnesses on an on-going basis 
- Grouping injuries and illnesses by nature, body part affected, event or exposure, source, etc 
- Determining if any trends in workplace injuries or illnesses exist and graphing those trends, if possible 
- Identifying any equipment, materials, or environmental factors that may be commonly involved in workplace injury or illness incidents 
- Identifying possible solutions and suggesting improvements to reduce or prevent the likelihood of future workplace injuries or illnesses.
Monitor and review
Whichever method of eliminating and/or controlling the hazard is used, it is essential that an evaluation of its impact on the use of the equipment, substance, system, or environment is carried out to ensure that the control does not contribute to the existing hazard or introduce a new hazard.
It is also essential that all people involved are informed about the changes and, when necessary, provided with the appropriate information, instruction, training, and supervision to ensure that each worker is safe from injury and risk to health. It is also recommended that after a period of time, the area supervisor carry out a review of the system or control to determine its ongoing suitability.
| Conclusion|| |
The first step for protection of workers against occupational diseases and maintaining a safe workplace is defining and analyzing hazards. There is a need for HIRAC study as a routine practice in all manufacturing industries. This helps in achieving two objectives; first is identifying the critical and high-risk hazards, which need to be addressed on priority basis, and second, by applying control measures at the earliest, it reduces the risk to a level considered ALARP.
I would like to express my deepest appreciation to the Managing Director of the Pellet Plant for encouraging me to conduct this study. I would like to thank the employees and the workers of the Pellet Plant for participating in the study. Finally, I take this opportunity to express my deep sense of gratitude and indebtedness to my beloved teacher and guide Dr. Barun Kumar Sikdar, Deputy Chief Inspector of Factories (Med) and Certifying Surgeon, West Bengal for his encouragement and support.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Material Safety Data Sheet (MSDS) Iron ore; Cliffs Natural Resources.
Material Safety Data Sheet (MSDS) Bentonite; Sciencelab.com, Inc.
Material Safety Data Sheet (MSDS) Lime.
Material Safety Data Sheet (MSDS) Furnace Oil.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]