Industrial Hygiene: Workplace Risk Management
Industrial Hygiene
Study of Workplace Risks
Industrial hygiene focuses on identifying, evaluating, and controlling environmental factors or stresses in the workplace that can cause illness, impair health, or affect well-being. It involves recognizing risks associated with physical, chemical, and biological agents.
Objectives and Principles
- Identify risks from physical, chemical, or biological agents.
- Quantify and assess workplace risks.
- Implement control measures to mitigate risks.
Chemical Agents
Chemical agents can be present in various forms:
- Solids (Dust and Aerosols): Organic and inorganic particles generated from processes like mining, construction, woodworking, and textile manufacturing.
- Liquids (Sprays and Mists): Liquid droplets dispersed in the air.
- Gases and Vapors: Substances that exist in a gaseous state at room temperature.
Physical Agents
Physical agents involve energy transfer to individuals, including:
- Noise
- Lighting
- Vibration
- Extreme temperatures
- Radiation
- Abnormal pressures
Biological Agents
Biological agents are living organisms or materials derived from living organisms that can cause harm, such as:
- Viruses
- Bacteria
- Parasites
- Fungi
- Protozoa
Health and Occupational Medicine
Health is a state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity (WHO definition).
Occupational medicine involves measuring and evaluating worker exposure to pollutants through biological samples like blood and urine.
Ergonomics
Ergonomics focuses on optimizing the fit between work and individuals to enhance efficiency and well-being.
Routes of Entry for Contaminants
Respiratory Route
The respiratory system is a primary route of entry for contaminants. We inhale a significant amount of air daily, making it crucial to control air quality in the workplace.
Dermal Route
The skin can absorb certain contaminants, especially those that are fat-soluble. Factors like skin thickness, wrinkles, and vascularization influence absorption.
Digestive Tract
Ingestion of contaminants can occur through smoking, eating with dirty hands, or exposure to dust and fumes.
Acute vs. Chronic Poisoning
Acute poisoning results from high-concentration exposure to a contaminant over a short period.
Chronic poisoning occurs with low-dose exposure over an extended period.
Chemical Hazards and Toxicity
A chemical hazard is any substance that can cause harm during manufacturing, handling, transportation, storage, or use.
Toxicity refers to the ability of a substance to cause damage to living organisms. The higher the dose, the greater the toxicity.
Phases of Poison Action
- Action on the organism (absorption, distribution, metabolism, elimination)
- Characteristic toxic effects on the body
Stages of a Toxin in the Body
Once toxins enter the body, they undergo several processes:
- Absorption
- Distribution and transportation
- Accumulation
- Metabolism
- Elimination
Absorption is the passage of the toxin into the bloodstream. This can occur through inhalation, skin contact, or ingestion.
Distribution and transportation involve the movement of the toxin throughout the body, often binding to specific organs.
Accumulation occurs when toxins build up in tissues over time, leading to prolonged effects even after exposure ceases.
Metabolism transforms toxins into metabolites, which are typically less toxic. Elimination removes toxins from the body through various routes, primarily the kidneys, liver (biliary system), and lungs.Toxic Action of Multiple Substances
- Single effects: Each toxin acts on a different organ.
- Additive effects: Toxins affect the same organ, with their effects combining.
- Potentiating effects: One toxin amplifies the action of another.
Classification of Toxic Effects
- Reversible: Biological changes caused by the toxin resolve upon cessation of exposure.
- Irreversible: Changes are permanent and do not revert to the normal state.
- Acute: Effects appear shortly after exposure.
- Chronic: Effects manifest after prolonged or repeated exposure.
Toxins can also be classified based on the type of damage they cause, such as corrosive, irritant, pneumoconiotic, asphyxiating, narcotic, sensitizing, carcinogenic, mutagenic, teratogenic, and systemic.
Industrial Hygiene Program: Recognition, Evaluation, and Control
Recognition
Involves identifying and understanding the environmental factors present in the workplace.
Evaluation
Includes measuring environmental factors and comparing results to established exposure limits.
Control
Implements corrective measures to eliminate or reduce exposure to acceptable levels.
Control Methods
Control at the Source
- Substitution of hazardous substances with less toxic alternatives
- Process modification to reduce or eliminate hazards
- Enclosing or isolating processes to prevent contaminant release
- Using wet methods to suppress dust generation
- Implementing proper maintenance practices
- Installing local exhaust ventilation systems
Control in the Environment
- Maintaining cleanliness and good housekeeping practices
- Providing general ventilation to dilute contaminants
- Increasing the distance between the source of contamination and workers
- Implementing alarm systems to warn of hazardous conditions
Control at the Worker Level
- Providing training and information on hazards and control measures
- Reducing exposure time through work rotation or administrative controls
- Using personal protective equipment (PPE) such as respirators, gloves, and protective clothing
- Promoting good personal hygiene practices
Branches of Industrial Hygiene
- Theoretical Hygiene: Studies contaminants and their interactions with the human body.
- Analytical Hygiene: Conducts qualitative and quantitative research on workplace exposures.
- Field Hygiene: Performs occupational hygiene studies, sampling, and workplace assessments.
- Operational Hygiene: Selects and recommends risk control methods for implementation in the workplace.
Occupational Diseases and Permissible Exposure Limits
Occupational diseases result from exposure to hazardous conditions in the workplace. Industrial hygiene aims to prevent these diseases by controlling exposure levels.
Permissible exposure limits (PELs) are established to define acceptable levels of exposure to chemical substances and physical agents. Employers are responsible for ensuring that worker exposures remain below these limits.
Objectives of an Industrial Hygiene Program
- Identify and control workplace hazards (chemical, physical, biological, psychosocial).
- Match job demands to worker capabilities and limitations.
- Protect vulnerable individuals and promote resilience.
- Detect and correct unhealthy working conditions.
- Educate management and workers on occupational health and safety.
- Implement comprehensive health programs.
Acute, Subacute, and Chronic Effects
Acute effects occur after short-term exposure to high doses of a contaminant.
Subacute effects are less severe than acute effects and may manifest after a delay following repeated exposures.
Chronic effects develop over time due to long-term exposure to low doses of a contaminant.
Supreme Decree No. 594: Regulations on Basic Health and Environmental Conditions in Workplaces
This decree establishes permissible exposure limits for chemical substances and physical agents in Chile. It outlines employer responsibilities for controlling exposures and protecting worker health.
The decree defines different types of exposure limits:
- Weighted Permissible Limit (LPP): Average exposure allowed over an 8-hour workday.
- Temporary Permissible Limit (LPT): Average exposure allowed over a 15-minute period.
- Absolute Permissible Limit: Maximum concentration allowed at any time.
The decree also provides guidelines for adjusting exposure limits based on work schedules and altitude.
Conclusion
Industrial hygiene plays a critical role in protecting worker health and safety by identifying, evaluating, and controlling workplace hazards. By implementing effective control measures and adhering to established exposure limits, we can create healthier and safer work environments for all.