Occupational Health and Safety

• Occupational health and safety adapts the working environment to workers to promote and maintain their physical, mental, and social well-being.

Definition of Terms

• WHO defines occupational safety and health as a multidisciplinary activity that aims to protect and promote workers' health by eliminating hazards, enhancing well-being, and developing sustainable work environments.
• ILO/WHO defines occupational health as the promotion and maintenance of the highest degree of physical, mental, and social well-being of workers in all occupations.
• Occupational health encompasses engineers, environmental health practitioners, chemists, toxicologists, doctors, nurses, safety professionals, and others.

Interdisciplinary Relationships

• Environmental managers work to eliminate workplace hazards that cause environmental problems.
• Toxicology studies poisons and toxic substances and their effects on living organisms
• Toxicologists define exposure levels at which harm occurs and prescribe precautionary measures.
• Ergonomics studies the interaction between humans and their total working environment, including atmosphere, heat, light, sound, tools, and equipment.
• Chemical engineers design process plants and decide on access and cleaning procedures.
• Mechanical engineers choose materials handling systems and specify noise levels on machinery.
• Environmental health professionals understand environmental health hazards and implement approaches to reduce human exposures and health impacts.
• Industrial hygienists protect the health of people in the workplace and the community.

Occupational Health and Development

• The health status of the workforce directly impacts national and world economies.
• Economic losses from occupational illnesses and injuries were estimated by the ILO in 1997 to be approximately 4-5% of the world’s Gross National Product.
• A healthy, well-trained, and motivated workforce increases productivity and generates wealth.

Magnitude of the Problem/Disease

• Obtaining accurate estimates of work-related diseases is difficult due to underreporting, unrecognized cases, and the implication of legal and economic responsibility.
• Globally, millions work in poor and hazardous conditions with 10,000,000 occupational disease cases occurring each year.
• Women, children, and migrant workers are disproportionately affected.
• Micro and small enterprises often have poor conditions and exclude workers from legal protection.
• Workplace issues include unsafe buildings, old machines, poor ventilation, and noise.
• Worker issues include limited education, skill, and training.
• Employer issues include limited financial resources and lack of attention/knowledge.

Principles of Occupational Health and Safety

• Occupational health and safety services should be preventive-oriented and multidisciplinary.
• Services should integrate with existing public health services and address environmental considerations.
• Services should involve participation from social partners and stakeholders.
• Services should be delivered using a planned approach.
• Services should be based on up-to-date information, education, training, consultancy, advisory services, and research findings.
• Services should be viewed as an investment that contributes to productivity and profitability.

Scope of Occupational Health and Safety

• Factory management spends significant expenses on health insured workers.
• Workers compensation expenses include medical payments, disability costs, death benefits, and legal costs.
• Cost claims may increase without intervention which will reduce productivity of the factory.
• Occupational health and safety aims to reduce costs through proper health service provision.
• The scope includes anticipation, recognition, and evaluation of workers’ health problems related to chemical, physical, biological, psychological, and ergonomic factors.
• Actions include corrective actions to eliminate or limit the problem.
• A multidisciplinary approach is required, involving knowledge of physics, biology, chemistry, ergonomics, medicine, engineering, and public health management.

Elements of the Work Environment

• Basic elements in an occupational setting include the worker, the tool, the process, and the work environment.
• Most workers are employed in informal sectors in developing countries like Liberia.
• There are high rates of unemployment, sometimes reaching 50% or higher.

Tool:

• Tools range from primitive to automated equipment.

Process:

• Materials used in the process can be toxic, and the process itself can affect their harmfulness.
• The particle size or physical state of substances can determine their potential ill effects.

Work Environment:

• Occupational environment includes external conditions and influences that affect the health of the working population.
• The work environment is becoming more complex.
• Interactions involve man and physical, chemical, and biological agents.
• Physical agents include noise, heat, humidity, dust, vibration, electricity, lighting, and radiation.
• Chemical agents include airborne concentrations of chemical dust, mists, fumes, liquids, vapors, and gases.
• Biological agents include insects, rodents, microorganisms, poisonous plants, and animals.
• Ergonomic hazards include improperly designed tools, work areas, or procedures.

Recognition of Occupational Health and Safety Hazards

• Identification of occupational health and safety hazards comes from observations of adverse health effects among workers.
• Potential problem areas must be identified and defined.
• The purpose of identification is to: Obtain information on occupational health stresses, collect information on working conditions, working conditions, processes and products, threshold limit values for substances, the effects of exposure on humans, and exposure levels by conducting elementary measurements.
• Identification lays the foundation of the evaluation of workers’ exposure in an area.
• Identification saves time, effort, and money.

Identification of Health and Safety Problems Includes

• Examining accident and near-miss records, sickness figures, and co-worker surveys.
• Using check-lists to inspect your workplace.
• Learn the results of inspections that are done by the employer, the union or anyone else.
• Reading reports or other information about the workplace.

Classifications of Occupational Health and Safety Hazards

• Physical Hazards
• Mechanical Hazards
• Chemical Hazards
• Biological Hazards
• Ergonomic Hazards
• Psychosocial Hazards

Physical Hazards

• Physical hazards adversely affect health, including noise, vibration, radiation, heat, and unhealthy microclimatic conditions.
• 10-30% of the workforce in industrialized countries and up to 80% in developing countries are exposed to physical hazards.
• Employers and inspectors should protect workers from adverse physical hazards.

Extremes of Temperature

• The work environment is either comfortable or extremely cold or hot and uncomfortable.
• The common physical hazard in most industries is heat.
• Extreme hot temperature affects those working in foundries or industries using open fire.
• Hot Effects of temperature in workplace

Heat Stress:

• People function only in a narrow temperature range.
• Fluctuation in core temperature impairs performance.
• The body counteracts by Heat stroke, Heat Cramp, Heat exhaustion.

Heat Stroke:

• Body temperature rises rapidly due to inability to cool itself sufficiently.
• Predisposing factors for heat stroke is excessive physical exertion in extreme heat condition.
• Method of control is therefore, to reduce the temperature of the surrounding or to increase the ability of the body to cool itself.

Heat Cramp:

• Results from exposure to high temperature for a relatively long time if accompanied by heavy exertion.
• Loss of salt and moisture from the body.

Heat Exhaustion:

• Results from physical exertion in a hot environment.

Signs include:

• Mildly elevated temperature
• Weak pulse
• Dizziness
• Profuse sweating
• Cool
• Moist skin, and heat rash

Cold Stress:

• The effect of the external working environment (Less than 6°C).
• The inability of the body to maintain a constant internal body temperature.
• High airflow is a critical factor, increasing cold stress effects considerably commonly referred to as the wind chill factor.
• Special condition that occur in cold weather include Trench Foot and Immersion Foot and Frostbite.

Trench Foot:

• Results from long exposure of the feet to continued wet condition at temperature of freezing 10 0 C with little movement causes changes in the circulation of blood in the feet.

Result:

• loss of toes or part of the feet. Treatment:
• Keep foot dry and warm, do exercise for good circulation.

Immersion Foot:

• Immersion of foot in water that is below 10 °C, for a prolonged time, usually in excess of 24 hours

Frostbite:

• Injury of tissue from exposure to intense cold, body parts most easily frostbitten is cheeks, nose, ears, chin forehead, wrists, hands and feet.

Prevention include:

• Wearing the proper amount warm, loose, dry clothing. wearing the proper amount warm, loose, dry clothing.
• Troops travelling in cold weather by, particularly in the rear of trucks should be allowed to dismount and exercise periodically to restore circulation.
• If clothing become wet, it should be dried or change at once

Vibration Motion Conditions

• Vibration causes vascular disorders of the arms and bony changes in the small bones of the wrist.
• Vascular changes can be detected by X-ray examination of the wrist.

Pressure –Atmospheric (High and Low)

• Exposure to increased atmospheric pressure (under water) leads to aseptic bone necrosis around the knee, hip, and shoulder that can be detected by X-ray examination

Ionizing and Non-Ionizing Radiation

• Radiation has a wide range of energies forms the electromagnetic spectrum with two major divisions: non-ionizing and ionizing radiation.
  • Not enough energy to remove electrons, is referred to as "non-ionizing radiation."
  • Sound waves, visible light, and microwaves
• Radiation that falls within the ionizing radiation has enough energy to remove tightly bound electrons from atoms. Alpha radiation:
  • Consists of helium-4 nuclei
  • Readily stopped by a sheet of paper. Beta radiation:
  • Consisting of electrons, is halted by an aluminium plate. Gamma radiation:
  • Eventually absorbed as it penetrates a dense material.
• Ionizing radiation is produced by radioactive decay, nuclear fission, nuclear fusion, extremely hot objects, and particle accelerators.
• Particles must have high energy and interact with electrons in order for radiation to be ionizing.
• Photons interact strongly with charged particles.

Electromagnetic radiation is the energy of a photon (i.e., a quantum of electromagnetic radiation to Planck to equation:

• The elements with the lowest and highest ionization potential are cesium (3.89 eV) and helium (24.6 eV), respectively.

Uses of Ionizing Radiation:

• An X-ray is ionizing radiation, and ionizing radiation can be used in medicine to kill cancerous cells
• The overuse of it can be hazardous to human health

Effects of ionizing radiation upon human health consist of Natural background radiation, Cosmic radiation, and Solar radiation Natural background radiation:

• It comes from cosmic radiation, solar radiation, external terrestrial sources, and radon. Cosmic radiation:
• The earth, and all living things on it, are bombarded by radiation from outside our solar system of ions.
• The energy of this radiation can far exceed energies that humans can create even in the largest particle accelerators.
• This radiation interacts in the atmosphere to create secondary radiation that rains down, including x-rays, muons, protons, alpha particles, pions, electrons, and neutrons

Solar radiation:

• Most solar radiation is electro-magnetic radiation.
• The sun produces particle radiation, solar particles, which vary with the solar cycle.
• Average composition is similar to that of the Sun itself
• Solar particles vary widely in their intensity and spectrum, increasing in strength after some solar events such as solar flares.

The effects of ionizing radiation on animals:

• Biological effects of radiation are thought of in terms of their effect on living cells
• The body repairs many types of radiation and chemical damage.

Biological effects of radiation on living cells may result in a variety of outcomes, including:

• Cells experience DNA damage and are able to detect and repair the damage experience DNA damage and are able to detect and repair the damage.
• Cells experience DNA damage and are unable to repair the damage by programmed cell death experience a nonlethal DNA mutation that is passed on to subsequent cell divisions to the formation of a cancer

Observations at the tissue level include:

• A small radiation dose reduces the impact of a subsequent, larger radiation dose this has been termed an 'adaptive response 'adaptive response
• Cells that are not 'hit' by a radiation track but are located nearby may express damage nearby may express damage term 'bystander effect'
• The progeny of a cell that survives radiation exposure may have increased probabilities for mutation.

Chronic radiation exposure:

• Exposure over an extended period of time.
• Natural background radiation is chronic exposure.
• Location and occupation often affect chronic exposure.
• Acute radiation exposure of ionizing radiation occurs during a short period of time.

Extreme examples include:

• Instantaneous flashes from nuclear explosions
• Exposures of minutes to hours during handling of highly radioactive sources
• Laboratory and manufacturing accidents
• Intentional and accidental high medical doses

General Class of Noise Exposure

• Occupational noise exposure may be grouped into Continuous noise, Intermittent Noise, and Impact (impulse) type Noise.
• Continuous noise is constant level and spectrum to which an employee is exposed for a period of eight hours per day or 40 hours a week.
• Intermittent Noise is given broadband sound pressure level several times during a normal working day.
• Impact (impulse) type Noise is a sharp burst of sound.

Effects of noise exposure:

• Health hazard in many occupational settings.
• Effects of noise on humans can be classified into Auditory Effects and Non-auditory Effects.

Non-auditory effects:

• Fatigue, interference with communication, decreased efficiency, and annoyance.

Auditory effects:

• Permanent or temporary hearing loss by explosive sounds or blasts.
• Excessive exposure produces hearing loss that involves injury to the hair cells in the organ of corti within the cochlea of the inner ear.

Prevention of noise exposure:

• OSHA requires a five phase hearing conservation program for industry: OSHA requires a five phase hearing conservation program for industryNoise Monitoring Audiometric (Hearing) Testing Employee Training Hearing Protectors Recordkeeping Noise Monitoring Audiometric (Hearing) Testing Employee Training Hearing Protectors Recordkeeping

Illumination

• Good and sufficient lighting is aimed at promoting productivity, safety, health, well-being, and pleasant working conditions at an economical cost.
• Luminance: The brightness on an object.
• Illuminance:is the amount of light
• Measured in lux.

Purpose of good lighting:

• Provide a safe working environment
• Provide efficient and comfortable seeing
• Reduce losses in visual performances

Effects of Poor Illumination: can include

• Direct glare,reflected glare from the work, dark shadows may lead to excessive visual fatigue, visual fatigue
• Causative factor in industrial accidents
• Delayed eye adaptation when coming from bright surroundings into darker ones.

Mechanical Hazards

• Unshielded machinery, unsafe structures, and dangerous unprotected tools.
• Applying simple measures can reduce accidents. However, ignorance has led to increasing rates of occupational accidents.

Chemical Hazards

• Annual world production of chemicals amounts to an estimated 400 million tones.
• There are between 5 to 7 million known chemicals,
• Market has 70,000 to 80,000.
• 5 to 10 % should be considered hazardous. Chemical hazards are dependent on amount, concentration, time of exposure, mode of entry to the body, age, sex, health status, and resistance of the exposed workers.

The effects of chemical agents are:

• Asphyxiation
• Systemic intoxication
• Pneumoconiosis
• Carcinogens
• Irritation
• Mutagenicity

Solvent

• Threat to the health, productivity, and efficiency of workers is their exposure to organic solvents.
• Exposure to solvents occurs throughout life.
• Organic solvent vapor inhaled by a mother could reach the fetus

Classification of Solvents:

• Materials used to dissolve another material and it includes aqueous or non-aqueous system. Includes those based in water. Include:
• Aliphatic hydrocarbons
• Halogenated hydrocarbons
• Aromatic hydrocarbons
• Cyclic hydrocarbons

The severity of a hazard in the use of solvents and other chemicals depends on:

• How the chemical is used.
• Type of job operation
• Duration of exposure
• Operating temperature
• Exposed body surface
• Ventilation rates
• Concentrations of vapors in workroom air
• House keeping

Health Effect

• The effect of solvents varies considerably with the number and type of halogen atoms present in the molecules. Carbon tetrachloride damages and causes liver cancer.
• The solvent should never be used for open cleaning processes.

Fire and Explosion

• Using non-flammable solvents can minimize the potential for this orsolvents with flash point greater than 60 degree Celsius or 140 degree Fahrenheit.
• The non-flammable halogenated hydrocarbons decompose when subjected to high temperature and give off toxic and corrosive decomposition products.
• Precaution must be taken to eliminate source of ignition.
• Electrical equipment should be insulated.

Dangerous Chemical Substances

• Many dangerous substances are used in industry, commerce, agriculture, research activities, hospitals and teaching establishments
• The classification of dangerous substances is based largely on the characteristic properties of such substances and their effects on man.
• Requires Provision provision of a specific pictorial symbol on any container or package.
• Terms used: Corrosive, Oxidizing, Harmful, Very toxic and toxic, Irritant, Highly flammable, and Explosive.

Corrosive:

• Hazard: Living tissues as well as equipment are destroyed on contact with these chemicals. Caution: Do not breathe vapors and avoid contact with skin eyes, and clothing.

Oxidizing:

• Hazard: ignite combustible material or worsen existing fire and thus make fire fighting more difficult. Caution: Keep away from combustible material. Restrict smoking in that area.

Harmful:

• Hazard: Inhalation and insertion of or skin penetration by these substances is harmful to heath. Caution: Avoid contact with the human body, including inhalation of vapors and in cases of malaise consult doctor.

Very Toxic and Toxic:

• Hazard: The substances are very hazardous to health whether breathed, swallowed or in contact with the skin and may even lead to death. Caution: Avoid contact with human body, and immediately consult a doctor in case of malaise.

Irritant:

• Hazard: May have an irritant effect on skin, eyes and respiratory organs
• Caution: Do not breathe vapors and avoid contact with skin and eye

Highly Flammable:

• Hazard: Substances with flash point less than 60 0 or 140 0F. Caution: keep away source of ignition.

Explosive:

• Hazard: Substances which may explode under certain condition. Caution: Avoid shock, friction, sparks and heat.