industrial hygiene

INDUSTRIAL HYGIENE

BY – IRAM DANISH SEMT-48 1

Definition ofOccupational / Industrial Hygiene

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• Definition 1 (International Occupational Hygiene Association By-laws – IOHA)

“ Occupational Hygiene is the discipline of anticipating, recognizing, evaluating and controlling health hazards in the working environment with the objective of protecting worker health and well-being and safeguarding the community at large.”

Definition of Industrial Hygiene

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• Definition 2 (American Industrial Hygiene Association - AIHA)

• “That science and art devoted to the anticipation, recognition, evaluation, and control of those environmental factors and stresses arising in or from the workplace, which may cause sickness, impaired health and well-being, or significant discomfort among workers or among citizens of the community”

Definitions – Industrial Hygiene

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IOHA AIHAOccupational Hygiene is the discipline of anticipating, recognizing, evaluating and controlling health hazards in the working environment with the objective of protecting worker health and well-being and safeguarding the community at large.”

Industrial Hygiene is “That science and art devoted to the anticipation, recognition, evaluation, and control of those environmental factors and stresses arising in or from the workplace, which may cause sickness, impaired health and well-being, or significant discomfort among workers or among citizens of the community”

What is the difference between Industrial hygiene and Occupational hygiene?

• The term Industrial Hygiene originated in the USA while in other parts of the world it is known as Occupational Hygiene.

• In some ways the term Occupational is a better description as health risks occur in all places that people work such as offices, shops, hospitals and farms, not just in places you would think of as industrial.

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Qualification of an Industrial Hygienist

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• A person having a college or university degree (s) in engineering, chemistry, physics, medicine or related physical and biological sciences, who has also received specialised training in recognition, evaluation, and control of workplace stressors and therefore achieved competence in industrial hygiene.

Basic Principles of Industrial Hygiene

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1. Anticipation of potential health risks

2. Recognition of existing health hazards at the workplace

3. Evaluation of health risks

4. Control of unacceptable risks

Remember the acronym: A.R.E.C.

Anticipation of potential risks

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• Best done –❒ in the design stage of a process or equipment or❒ at the formulation stage of a new substance or

chemical

Advantage: Eliminate the need for review or redesigning, thus save high costs.

Anticipation of potential risks

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• Basic information to consider:❒ Characteristics of the process or equipment❒ Physical and chemical properties of the formulation❒ Adverse health effects from past experience and

reported cases of occupational diseases and poisoning

• The process of anticipation is not easy and requires vast experience. Need to engage the assistance of experts such as the industrial hygiene practitioner, toxicologist and occupational health doctor.

Recognition of Health Hazards

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• This may be achieved through –a. Workplace inspection

i. Look at workplace environment, work processes,types of materials & equipment used;

ii. Observe workers at work

Recognition of Health Hazards

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b. Health surveillance and area monitoring

c. Workers health recordsd. Review of past Incident investigation reports.e. Discussion with the management and workers

Area Toxic Gas Monitoring

Harmful Factors that exist at the Workplace

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• Many workers may be exposed to a number of health hazards at work.

• Hazard recognition :– Identifying factors or work processes that may be harmful

to health.– Knowledge of the physicochemical properties of a material/

substance, its harmful effects to health and identification techniques are essential.

Health Hazards encountered at Work

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1. Chemical Substances

2. Physical agents.

3. Biological agents

4. Ergonomics

5. Psychological factors.

Chemical Hazards

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• Hazards – risks are associated with the use of chemicals.• Hazardous chemicals may cause –

✓ Fire & Explosion✓ Adverse health effects✓ Damage to the environment

Forms of Chemicals• Dust,• Particles and smoke• Liquid and mists• Gas and vapour

Common Types1. Solvents2. Metals3. Acids and Bases4. Pesticides

Physical Hazards

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Excessive exposure to the following physical hazards may cause harm to our health –

✓ Noise✓ Vibration✓ Ionising radiation

▪ Cosmic rays – gamma, alpha, Beta and X-rays;▪ soil/rock radioactive elements– uranium, thorium, radium,

potassium-40;▪ Man-made nuclear radiation

✓ Non-ionising radiation▪ UV, Infrared, microwave, laser.

✓ Lighting✓ Extremely high/low temperature✓ Extremely high/low air pressure

Biological Hazards•

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Micro organisms– Bacteria, viruses and Parasites.– The virus of contagious diseases may spread

through its vectors.Toxins (spider, snake, scorpion, jellyfish, wasp) Plants (fungi, yeast, cotton dusts)

Bacteria Anthrax, legionnaire’s disease, botulism, E.Coli, salmonella

Viruses H5N1(Avian Flu), SARS, HIV, mumps, Dengue fever. Hepatitis A/B/C , Variecella (chickenpox)

Fungi Poisonous mushrooms- Amanita virosa (Destroying Angel),– Amanita phalloides (Death Cap)

Parasites Malaria, mites, leeches, intestinal worms

Ergonomic Hazards

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Musculoskeletal disorders affecting workers mayarise from unsuitable work conditions or physical incapacity to carry out their assigned tasks.

1. Awkward body postures

Ergonomic HazardsExamples of unsuitable work conditions or physical incapacity:

4 Poor lightning and cramp work place18

2. Manual lifting of heavy loads

3. Repetitive hand Movements

Psychological hazards

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Tensions at the workplace may disturb the concentration and mental health of the worker

Examples of Tensions at the workplace✓ Monotonous work✓ Excessive workload and overtime✓ Poor work relationships with colleagues and

supervisors✓ Shift work✓ Remuneration and annual leave issues✓ Sexual Harassment

Objectives of Risk Evaluation (Assessment)

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• To determine the level of worker exposure (high, medium or low) to health hazards and the effectiveness of the existing control measures, and their relationship to the risk of disease.

• To enable decisions to be made on additional control measures to bring the health risks down to within PEL (Permissible Exposure Limit).

– e.g. engineering control to reduce airborne contaminants, worker training, health surveillance.

Risk Evaluation – what to look at?

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Risk = Hazard x Exposure

Hazard Component= Magnitude of hazard and the potential adverse health effects from

possible routes of entry or contact.

Exposure Component= Chances of overexposure occurring by taking into account:

i. Characteristics of exposure

ii. Level of exposure

Risk Conclusion – takes into account the work practices and personal factors including individual susceptibility.

Risk Evaluation

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(i) Characteristics of exposure✓ Who are exposed (based on Job types and tasks

performed)?✓ How many are exposed?✓ What are they exposed to?

✓ How are they exposed?€ Inhalation€ Skin Absorption€ Ingestion

Risk Evaluation

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(ii) Level of Exposure• Frequency of exposure

– daily, weekly, monthly?

• Duration of exposure– by seconds, minutes, hours?

• Intensity of exposure– high, medium, low?

Risk Evaluation

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(ii) Level of Exposure– Exposure intensity -

Quantitative• Using equipment to measure

the intensity or magnitude of exposure

Field Sling Psychrometer

– Exposure intensity - Qualitative• Using observation and

professional opinion

Risk Conclusion

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• Risk conclusion is made after taking into account

i. Level of risk exposure (high, medium or low) based on qualitative or quantitative assessment and rated against the Industry accepted Permissible Exposure Limits.

ii. The work practices, and personal factors (including individual susceptibility)

ii. The adequacy of existing control measures

Control of Health Risks

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Principle of Risk Control• Prioritise the control measures at the source, not the

worker• Prioritise the elimination of hazards, not the

reduction of exposure• Controls should target below the permissible

exposure limits• Controls should be as low as reasonably practicable,

especially in cases where there is no data on the permissible exposure limit

• Use of personal protective equipment (PPE) as a last resort

Principle of Risk Control

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1.Prioritise the control measures at the source, not the worker❒ Controlled source means –

€Controlled exposure€ A hazard free environment

❒ It is easier to control processes, machinery and equipment than to control workers


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2. Prioritise the elimination of hazards, not the reduction of exposure❒ No hazard means no exposure❒ Elimination of hazards is more effective❒ Reduction of exposure is only recommended where

it is not possible to eliminate or isolate the hazard


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3. Controls should target below the permissible exposure limits❒ Risk is reduced if worker exposure is below the

permissible limits❒ Exposure beyond the permissible limits is harmful to

worker health❒ Violation of Regulations, if PEL is exceeded


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4. Controls should be as low as reasonably practicable , especially in cases where there is no data on the permissible exposure limit

❒ The risk of cancer or allergy exists even at low exposure levels

❒ Hazard free environment is still the best working environment

❒ Many chemicals do not have permissible exposure limits

Hierarchy of Risk Controls

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• It is a list of protection strategies that are rated in order of priority from the best to the worst.

1. Elimination2. Substitution3. Isolation4. Engineering controls5. Administrative controls - Safe work practices and

procedures6. Personal Protective Equipment (PPE)

Other Methods to increase the levels of Control on health risk at the Workplace

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• Provide Information, instruction and training to workers.• Exposure monitoring• Health surveillance• First aid and emergency facilities• Warning signals

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