OCCUPATIONAL HYGIENE – Lesson 5

WHAT IS OCCUPATIONAL HYGIENE?

The science devoted to the anticipation, identification, evaluation and control of occupational factors or stressors arising in or from the workplace which may cause discomfort, sickness, or affect the well-being  among workers.

OCCUPATIONAL HYGIENE ACTIVITIES

Conduct Risk Assessments, namely:

• Qualitative risk assessments – this involves interviews of workers (subjective assessment of risks)
• Quantitative risk assessments – Using instruments

Evaluate risks – Analyzing data from qualitative and quantitative risk assessments

Control of risks – follow the hierarchy of controls, that is Elimination, Substitution, Isolation, Engineering and Administrative controls, PPE)

Conduct awareness – Ensure all persons are aware of hazards and risks

1: CHEMICALS EXPOSURE

These include:

• Dust e.g. Crystalline Silica, Asbestos, Lime etc.
• Organic/Inorganic substances
• Mists (Aerosol e.g. acid mists)
• Fumes (Airborne particles e.g. Lead)
• Diesel particulate matter e.g. unburned hydrocarbons etc.
• Volatile organic compounds e.g. Xylene in Paints

Dust

• These are solid particles suspended in air and are generated by mechanical processes such as crushing, grinding, conveying, abrasion or blasting.

Health hazards from exposure

• Chronic obstructive lung disease
• Emphysema
• Chronic bronchitis
• Cancer- Silicosis, Asbestosis

Organic/Inorganic Compounds

• These are solid or aerosol particles suspended in air and are generated by condensation from volatilized substances, spraying, or agitation of substances, diesel-powered vehicles etc.

Health hazards from exposure:

• Chronic obstructive lung disease
• Emphysema
• Chronic bronchitis
• Chemical burns
• Lead poisoning

2 :EXPOSURE TO PHYSICAL HAZARDS

Effects difficult to observe –  Cause Irreversible Damage

Noise

• Noise is unwanted sound. In a workplace, noise can be generated by many sources like running engines, vibrating loudspeaker diaphragms, operating machine tools etc.

What are Noise Zones?

• These are demarcated areas where noise levels can be equal to or above 85dB[A]
• You must look out for the symbolic safety signs which warn you to wear your Hearing Protection Devices in areas declared to be high noise zones.

What is Noise Induced Hearing Loss?

Noise Induced Hearing Loss

• Workers in confined spaces typical of the underground situation are daily exposed to the high noise levels of mining equipment and machines such as Rock Drills, Diamond Drilling Machines, Pumps, Loaders, Auxiliary Fans, Invert Drilling Machines, and Trackless Equipment.
• As the number of machines has grown, and their size and speed increased, noise has become more and more a problem.
• Innovative designs of the latest machinery and equipment takes operating noise levels into consideration, but still does not address this enough.

What is noise Induced Hearing Loss?

• Normal hearing is defined as a binaural average hearing threshold level equal to or better than 2dB.
• If exposed to noise levels of 105dB or more,
•  Noise Induced Hearing Loss will occur and if exposed to 85dB it may cause Noise Induced Hearing Loss.
• Hearing loss is unlikely to occur if an individual is exposed to 85dB or less during a 40 -hour week (8 hours per day).
• Hearing loss may occur if the 85dB level is exceeded to significant levels for long time periods.

Symptoms of hearing loss:

• Hearing becomes difficult
• People do not speak clearly – maybe mumble
• Dull feeling in ears and head
• Experience dizzy spells
• Hear noises in ears when it is quiet
• Hear better with one ear
• Difficulty to distinguish where sound comes from
• Speech changes e.g. speak louder or softer for no reason

What are the effects of Noise Induced Hearing Loss [NIHL] in the workplace?

• Cannot hear Warning Signals therefore puts Employee in danger.
• Problems in hearing instructions given for Safe Work.

Therefore: Increased risk of accidents.

Sources of  NOISE  in  a Mining and Processing Environment

• Ventilation Fans
• Compressed  Air [Rock drills  and  leaking  pipes]
• Scraper Winches
• Locomotives [Ore  tramming  and  material  handling]
• Mechanical  ore  handling  equipment
• Ore  tipping  and  Ore  Pass  transfers
• Workshops:  grinding,  hammering,  cutting
• Construction  and  maintenance  operations
• Machinery,  i.e. pumps , compressors,  electric  motors
• Milling
• Some  smelting  operations  (e.g.  Converters).

How can NOISE  affect your HEALTH?

When we are exposed to high level noise for a short duration, we  experience temporary hearing loss.

• BUT when we are exposed to noise,  (equal or above 85 decibels [DBA]) every workday,  we experience deterioration in our hearing and eventually permanent hearing loss.
• Noise in the workplace may impair our recognition of wanted sound such as speech communication and warning signals.

Noise also has an effect on your body functions

• Noise will  stimulate  hormones in the body which increase the heart rate and constricts  the veins in which the blood flows.
• The continuation of this state places  heavy demands on the reserves of the body and leads  to fatigue and even disturbed sleep patterns.

EXPOSURE  to  Noise  can  affect  PRODUCTION!

What are its limitations?

• Ear plugs are designed for only short-term use, e.g. half an hour (they can be used for longer for protection against lower levels of noise). For very high noise levels, e.g. from jet engines, ear defenders must be used. Some people find ear plugs uncomfortable, and they can increase the risk of ear infection if they are not kept scrupulously clean.
• Ear defenders sometimes become uncomfortable in hot working environments and will only reduce the noise level — not eliminate it. You must make sure they fit correctly, with the seals fully in contact with the side of your head.

Where must hearing protection be worn?

• You should wear hearing protection wherever you are likely to come up against loud noise while you work. The most obvious area is on airport tarmac, where even brief exposure to the sound of a jet engine can lead to prolonged or irreversible damage to hearing. Prolonged exposure to moderate noise levels may also cause permanent damage. Under health and safety legislation, certain areas are designated as ‘ear defender zones’.

Illumination

• Defined as the action of supplying or brightening a workplace. Illumination is required at all places where personnel are required to work or travel.

Occupational hazards related illumination:

Poor lighting high or low can cause several problems such as:

• Discomfort – too much or too little light strains eyes and may cause eye discomfort (burning, etc.), headaches, dizziness and loss of night vision.
• Eye strain due to insufficient light to see the task.  Poor lighting can affect the quality of work, specifically in situation where precision is required, and overall productivity.
• Glare – too much light for the need.

Vibration:

This is a rapid linear motion of a particle or of an elastic solid about an equilibrium position. In a mining, vibrations are caused   by moving equipment such as haul trucks, bulldozers, loaders etc. and hand tools like rock drills, jackhammers, etc.

Health hazards from exposure to vibration:

• Whole body vibration – discomfort, interference with activities and motion sickness, back problems, disorders of the digestive and reproductive systems to visual and nervous system problems.
• Hand-arm vibration include bone, joint, neurological, muscular and vascular disorders such as vibration-induced white finger.

Occupational Thermal Environment

Defined as those aspects of the workplace that include local temperature, humidity, and air velocity as well as the presence of radiating surfaces. In underground mining, thermal conditions are measured in all confined spaces.

Occupational hazards

• Fatigue/poor productivity
• Heat disorders like heat cramps, heat exhaustion and heat stroke
• Frostbite
• Hypothermia

HEAT STRESS

What is it and how it affects you?

Hot weather and conditions can bring a host of hazards.

Protect yourself from the heat!

EXTERNAL FACTORS AFFECTING HEAT STRESS

• Air movement
• Clothing
• Radiant heat (hot vessels and sun)
• Humidity
• Work rate (mild/moderate/heavy)

HEAT STRESS

How to cope with heat

It is that summer again when we have to worry about the heat and its effects.  Working under hot and humid conditions places a lot of stress on the body which can result in minor or life threatening illnesses.

Being aware of the various types of illnesses, symptoms and preventive steps will help you deal with the heat.

HEAT STRESS – GENERAL PRECAUTIONS

Hydration – The best way to avoid heat strokes and other heat disorders is to keep your body well hydrated. Drink a lot of water if you are exercising or working in  hot conditions. Doctors usually recommend consuming eight or more glasses of water per day.

Ventilation – Remain in cool areas where your body can cool itself. If working in  hot conditions, try to take a break to regain energy and to avoid overexposure to the sun.

Clothing – What you wear plays a big factor in how your body handles the heat. Light clothing and loose-fitting clothing will help your body in breathing and cooling itself. It is fine to wear a hat or cap to protect yourself from the sun but once you feel warm, remove it. This usually traps the heat inside your body.

HEAT STRESS

Limit yourself

• It is also important to watch the amount of activities you are participating in during hot days. Don’t overdo it. Heat stroke and other disorders can take effect in less than an hour. If you feel warm or dizzy, it’s best to take time to rest.

Are you fit to work during summer?

• Older employees, obese employees, new employees and personnel on medication are at great risk if they decide to work during very hot and humid conditions.

HEAT STRESS

Treatment:

• With enough fluids and rest this illness is self correcting
• Drink fluid slowly, as the body will absorb it better.
• If heat exhaustion is not properly treated, it may become Heat Stroke, which is  deadly.  If the person’s temperature goes above 39°C then treat them for heat stroke!
• Limit yourself. It is also important to watch the amount of activities you are participating in during hot days. Don’t overdo it. Heat stroke and other disorders can take affect in less than an hour. If you feel warm or dizzy, it’s best to take time to rest.

Are you fit to work during summer?

• Older employees, obese employees, new employees and personnel on medication are at great risk if they decide to work during very hot and humid conditions.

HEAT EXHAUSTION

Heat exhaustion is similar to, and often follows, dehydration. It’s what happens when you’re losing more fluid and electrolytes than your body can handle.

Symptoms

• Sweating
• Increased pulse and respiration
• Pale and clammy skin
• Nausea and vomiting
• Light-headedness and dizziness
• Possible heat cramps
• Feeling thirsty

HEAT STROKE

Heat stroke is a life-threatening emergency, and victims can die in just 30 minutes so help must be given quickly. Heat stroke is caused by an increase in the body temperature to about 41°C. Temperatures over 41.5°C can lead to death. This increase in temperature causes the brain to overheat. There are two types of heat stroke:

• fluid depleted (slow onset) and fluid intact (fast onset).

TREATMENT

• The most important thing to do is begin to lower the body temperature
• Pour cool (NOT cold) water over the person’s extremities. If water is limited cool off the head and neck area first. Also, try fanning the person to increase air circulation and speed up sweat evaporation.
• Get the person to a medical facility as soon possible

SYMPTOMS

• Hot and Red skin. Some victims will have hot dry skin (common in the elderly) and others will have hot wet skin (if, for example, they were previously suffering heat exhaustion) in all cases, however the skin should look red
• Pale skin
• Pulse and respiratory rates increase
• Argumentative
• Disoriented
• Increased temperature
• Hallucinations
• Dilated and unresponsive pupils
• Seizures, which may lead to the person becoming comatose

Radiation

This is energy that travels through some material or through space e.g. light, heat. Another type of radiation is called Ionizing radiation and comes from charged particles (ions) in matter e.g. alpha, beta and gamma/x-ray radiation and is emitted by materials like Uranium, density gauges and  X-ray devices .

Health hazards from radiation:

• Cancer and genetic defects because radiation damages and alters the body’s normal cells and normal cell functions.
• In pregnancy may cause birth defects, miscarriage, intellectual disability, decrease in IQ, a higher risk of childhood cancer and cancer in adult life.

3: ERGONOMIC FACTORS

Ergonomics is the process of designing or arranging workplaces, products and systems so that they fit the people who use them.

Health hazards from poor ergonomic design

• Pain in the fingers, wrists, or other parts of the body: may include a dull aching pain, a sharp stabbing pain, or even a burning sensation.
• Tingling or numbness, particularly in the hands or fingers, discomfort when making certain movements.
• Swelling, inflammation, or joint stiffness.
• Loss of muscle function or weakness.
• Discomfort or pain in the shoulders, neck, or upper or lower back.
• Range of motion loss, clumsiness or loss of coordination extremities turning white or feeling unusually cold, general feeling of muscle tightness, cramping, or discomfort.

4: BIOLOGICAL FACTORS

Biological hazards

These hazards arise when employees are exposed to biological agents such as bacteria, fungi, viruses etc. due to exposure to poor sanitation, through contact, ingestion and personal hygiene.

Health hazards from  exposure

• Worm infestations such as giant roundworms (ascaris lumbricroidis)
• Diarrhoeal diseases such as dysentery, cholera- contaminated water
• Skin infections such as athletes foot- poorly cleaned boots and showers
• HIV & AIDs , Ebola- viral infections, Corona Virus

5: PSYCHOLOGICAL FACTORS

Psychological factors refer to thoughts, feelings and other cognitive characteristics that affect the attitude, behavior and functions of the human mind.

Health risks

• At individual level- low self esteem, emotional immaturity, medical illness leading to substance abuse
• At social level- loneliness/bereavement, neglect & family conflict, low income leading to poverty
• At work- absenteeism, poor productivity due to lack of concentration

OCCUPATIONAL HYGIENE: RISK ASSESSMENTS

Quantitative risk Assessments:

• A continuing programme of observation, measurement and judgement to recognise health hazards and evaluate adequacy of control measures.
• Instruments are an essential part of identification, evaluation & control process

RISK ASSESSMENTS: PERSONAL MONITORING

• Measurement of employee’s exposure – to assess risk.
• Measuring device are placed close to port of entry of contaminant.

AWARENESS PROGRAMS

Target employees are those in high risk areas and the objective is to heighten awareness on associated risks and approved PPE

Current programmes target:

• Inductions
• Workshops on:
  -Dust
  -Noise