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Occupational lung diseases are an important public health issue and are avoidable through preventive interventions in the workplace.
Up-to-date knowledge about changes in exposure to occupational hazards as a result of technological and industrial developments is essential to the design and implementation of efficient and effective workplace preventive measures.
New occupational agents with unknown respiratory health effects are constantly introduced to the market and require periodic health surveillance among exposed workers to detect early signs of adverse respiratory effects. In addition, the ageing workforce, many of whom have pre-existing respiratory conditions, poses new challenges in terms of the diagnosis and management of occupational lung diseases.
Primary preventive interventions aimed at reducing exposure levels in the workplace remain pivotal for elimination of the occupational lung disease burden. To achieve this goal, there is still a clear need for setting standard occupational exposure limits based on transparent evidence-based methodology, in particular for carcinogens and sensitising agents that expose large working populations to risk.
To manage the respiratory related hazards, Respiratory Protective Equipment (RPE) will play a key role. To ensure effective respiratory protection, proper selection of RPE, proper training for workers, appropriate maintenance and inspection are required. This article elucidates about respiratory hazards, respiratory protection and worker behavioural analysis in wearing RPE.
Category of Respiratory Hazards
The three categories of respiratory hazards that could affect a workplace: oxygen-deficient atmospheres, gas or vapour workplace respiratory hazards, and particulate contamination workplace respiratory hazards.
Respiratory hazards can exist in various forms at general industry worksites. They may be gases, vapours, dusts, mists, fumes, smoke, sprays, and fog.
Oxygen-Deficient Atmospheres
The definition of an oxygen-deficient atmosphere is any atmosphere where there is less than 19.5% oxygen in the air. Oxygen-deficient atmospheres are dangerous. Working in an oxygen-deficient atmosphere can cause the following effects:
Judgement and logic are impacted first as your brain starts to lose oxygen
- Next, you may feel disoriented and have trouble seeing or hearing
- Finally, sustained exposure to an oxygen-deficient atmosphere can lead to unconsciousness, or even death, if you are not removed from the hazardous environment and given the oxygen you need
Common examples of oxygen-deficient conditions are confined workspaces including, but not limited to, silos, sewers, manholes and tanks.
Workplace Respiratory Hazards
To define gas and vapour respiratory hazards, gases are a natural physical state of a material that is evenly distributed in air at room temperature, whereas vapours are contaminants formed from the evaporation of liquids into the air. Both gases and vapours may exist as airborne contaminants, are usually invisible, and are difficult to detect due to their lack of odour, colour, or taste.
“respiratory hazards can exist in various forms at general industry worksites”
Both gases and vapours can be absorbed into the bloodstream, which can cause damage to your blood or internal organs, contributing to serious health effects, or even death. Common examples of industries and applications affected by gas or vapour hazards are any application that works with chemicals, such as in laboratories, construction, manufacturing and agriculture.
Particulate Contamination Workplace Respiratory Hazards
The definition of a particulate contaminant respiratory hazard is any environment where an air contaminant is present. Common particulate contaminant hazards include dusts that are found everywhere and are formed whenever solid matter is broken down by either natural or mechanical forces.
Fumes are very small metal particles that are released into the air when metals are heated. Smoke is produced when materials are burned. Burning creates a combination of gases, vapours, and very small particles that create a hazardous environment. Mists are small droplets of airborne liquids that are formed by spraying or mixing chemicals.
Health effects associated with particulate contamination can vary depending on the types of particulate contaminating your workplace environment. Common adverse health effects include:
- Decreased lung function
- Increased respiratory symptoms
- Irritation of the airways
- Coughing
- Difficulty breathing
Some particulate contamination hazards are also associated with long-term health risks like heart and lung diseases. Common examples of tasks or industries frequently exposed to particulate contamination hazards are spray painting, the use of dip tanks for coating or metal treatment, welding, soldering, smelting, and working in or near smoke. They also include working around any kind of dust, allergen, or irritant.
Hazardous Substances in Workplaces
Inhalation of chemicals occurs by absorption of chemicals via the respiratory tract (lungs). Once chemicals have entered into the respiratory tract, the chemicals can then be absorbed into the bloodstream for distribution throughout the body.
Chemicals can be inhaled in the form of vapours, fumes, mists, aerosols and fine dust. Symptoms of exposure to chemicals through inhalation include eye, nose, and throat irritation, coughing, difficulty in breathing, headache, dizziness, confusion, and collapse.
If any of these symptoms are noted, leave the area immediately and get fresh air. Seek medical attention if symptoms persist and complete an Injury/Illness Report.
Occupational exposures that affect the respiratory health of workers occur in many forms and in many different types of work settings. Respiratory exposures are in the form of dusts, vapours, fumes, and bio aerosols, and can include materials such as silica, asbestos, coal, pesticides, and flavourings. The type and severity of respiratory illness or disease depends on the type of work being performed during inhalation, the type of substance that is inhaled, how long the substance is inhaled, and the location of the lung where the substance lands.
“once chemicals have entered into the respiratory tract, the chemicals can then be absorbed into the bloodstream”
Aerosols, as used here, is a suspension of tiny particles or droplets in the air, such as dusts, mists, or fumes. These particles may be inhaled or absorbed by the skin and can sometimes cause adverse health effects for workers.
Anthrax is an acute infectious disease caused by the spore-forming bacterium Bacillus anthracis (B. anthracis). B. anthracis spores are highly infective and can cause inhalation, cutaneous, or gastrointestinal anthrax.
Inhalation anthrax results from breathing in spores and is of great concern due to its high fatality rate.
When handled, asbestos can separate into microscopic-sized particles that remain in the air and are easily inhaled. Persons occupationally exposed to asbestos have developed several types of life-threatening diseases, including asbestosis, lung cancer and mesothelioma.
Some workers exposed to beryllium dusts and/or fumes may develop an immune response known as sensitisation, which can be detected in the blood with the beryllium lymphocyte proliferation test (BeLPT). Some sensitised workers may have or may develop chronic beryllium disease (CBD), a slowly progressive respiratory disease characterised by the formation of lung lesions called granulomas. These granulomas and accompanying fibrosis cause impairment of the lung’s ability to expand fully and to oxygenate the blood.
Blood borne infectious diseases may occur on exposures to blood and other body fluids occurring across a wide variety of occupations. Health care workers, emergency response and public safety personnel, and other workers can be exposed to blood through needle stick and other sharps injuries, mucous membrane, and skin exposures.
The pathogens of primary concern are the human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). Workers and employers should take advantage of available engineering controls and work practices to prevent exposure to blood and other body fluids.
Indoor Environmental Quality (IEQ) in the office environment may have the potential to release volatile organic compounds (VOCs). There are a variety of chemical contaminants found in a variety of sources. VOCs are common chemical contaminants found in office and home environments and are a source of odours.
VOCs are organic (containing carbon) chemicals that can easily evaporate into the air. Many products found in the office environment may have the potential to release VOCs. Examples include caulks, sealants, coatings, adhesives, paints, varnishes and/or stains, wall coverings, cleaning agents, fuels and combustion products, carpeting, vinyl flooring, fabric materials and furnishings, air fresheners and other scented products.
“asbestos can separate into microscopic-sized particles that remain in the air and are easily inhaled”
If these and other chemical contaminant sources are not controlled, indoor environmental quality problems can arise, even if the building’s ventilation system is properly designed and well maintained.
Coal mining-related respiratory diseases can affect the gas exchanging tissues of the lungs. These lung tissues remove carbon dioxide and take up oxygen. The diseases can also affect the lung passages that carry air back and forth during breathing.
The passages are called airways. Depending on what is in the coal mine dust that is inhaled and the part of the lung that is affected, coal miners may develop several different types of respiratory diseases.
Pneumoconiosis refers to fibrotic (scarring) disease of the lung tissue caused by inhalation of respirable-sized mineral dusts. The primary pneumoconiosis seen in coal miners are coal workers’ pneumoconiosis and silicosis.
Diesel exhaust is a complex mixture of compounds and can be regarded as “a potential occupational carcinogen and its composition varies greatly with fuel and engine type, load cycle, engine maintenance, tuning, and exhaust gas treatment. This complexity is compounded by a multitude of environmental settings in which diesel-powered equipment is operated.
“respiratory diseases can affect the gas exchanging tissues of the lungs”
Isocyanates are a family of highly reactive, low molecular weight chemicals. They are widely used in the manufacture of flexible and rigid foams, fibres, coatings such as paints and varnishes, and elastomers, and are increasingly used in the automobile industry, auto body repair, and building insulation materials.
Spray-on polyurethane products containing isocyanates have been developed for a wide range of retail, commercial, and industrial uses to protect cement, wood, fiberglass, steel and aluminium, including protective coatings for truck beds, trailers, boats, foundations, and decks.
Isocyanates are powerful irritants to the mucous membranes of the eyes and gastrointestinal and respiratory tracts. Direct skin contact can also cause marked inflammation. Isocyanates can also sensitise workers, making them subject to severe asthma attacks if they are exposed again.
Metal working fluids (MWFs) are used to lubricate, cool, prevent corrosion of, and remove chips from tools and metal parts during grinding, cutting, or boring operations. There are several types of MWFs: straight or soluble oils, semisynthetic oils, and synthetic oils. Exposures to MWFs can occur through inhaling aerosols, skin contact with contaminated surfaces, and splashing of fluids. Employees who have been exposed to MWFs often report skin disorders (skin irritations, oil acne, and rashes); eye, nose, and throat irritation; and respiratory symptoms (cough, asthma, or other breathing problems).
Selection, Types and Maintenance
A respiratory protection device, also known as a respirator, is an article of personal protective equipment (PPE) designed to prevent a worker from inhaling contaminated air. It functions by either covering the nose and mouth, or the entire face or head to protect the worker against hazardous air bone substances.
To protect the workers from the hazardous substances and also in oxygen deficient or in toxic gas ambiences, respiratory protective equipment (RPE) will play a key role. The selection of respirators are based on the form of the contaminant, toxicity level of the contaminant, the concentration of the contaminant, duration of exposure and the individual sensitivity to the contaminant.
There are two main types of respirators: air-purifying respirators and air-supplied respirators. Respirators (filtering device) use filters to remove contaminants in the workplace air, and there are two main types:
- Non-powered respirators rely on the wearer’s breathing to draw air through the filter
- Powered respirators use a motor to pass air through the filter to give a supply of clean air to the wearer
Breathing apparatus (BA) needs a supply of breathing-quality air from an independent source (e.g. air cylinder or air compressor). Both respirators and BA are available in a range of different styles, which can be put into two main groups:
- Tight-fitting face pieces (often referred to as masks) – rely on having a good seal with the wearer’s face. These are available as both non-powered and powered respirators and BA. Examples are filtering face pieces, half and full-face masks.
- Loose-fitting face pieces – rely on enough clean air being provided to the wearer to prevent contaminant leaking in (only available as powered respirators or BA). Examples are hoods helmets, visors, blouses and suits.
Elastomeric Half Face piece respirators are usable and have replaceable cartridges or filters. They cover the nose and mouth and provide protection against gases, vapours, or particles when equipped with the appropriate cartridge or filter. They are reusable and have replaceable canisters, cartridges, or filters. The face piece covers the face and eyes, which offers eye protection.
Filtering Face piece respirators are disposable half-face piece respirators that filter out particles such as dusts, mists, and fumes. They do not provide protection against gases and vapours.
Powered Air-Purifying Respirators (PAPRs) have a battery-powered blower that pulls air through attached filters, canisters, or cartridges. They provide protection against gases, vapours, or particles when equipped with the appropriate cartridge, canister, or filter. Loose-fitting PAPRs do not require fit testing and can be used with facial hair.
Supplied-Air Respirators are connected to a separate source that supplies clean, compressed air through a hose. They can be lightweight and used while working for long hours in environments not immediately dangerous to life and health (IDLH).
Self-Contained Breathing Apparatus (SCBAs) are used for entry into or escape from environments considered to be IDLH. They contain their own breathing air supply and can be either open circuit or closed circuit.
Combination respirators can be either a supplied-air/SCBA respirator or supplied-air/air-purifying respirator. The SCBA type has a self-contained air supply if primary airline fails and can be used in IDLH environments. The air-purifying type offers protection using both a supplied-air hose and an air-purifying component and cannot be used for entry into IDLH environments.
Effective maintenance of RPE is required to ensure that the equipment continues to provide the degree of protection for which it was designed. Maintenance includes cleaning, disinfection, examination, repair, testing, and safe storage. Maintenance details are usually provided by the manufacturer.
The RPE should be examined before each use, with particular attention being paid to all rubber parts such as face pieces, exhalation valves, breathing tubes, and head harnesses. If the equipment is in a bad condition, it should not be used.
Where ‘tight fit’ RPE, e.g. breathing apparatus, respirators and filtering face pieces are used it must be fit tested to confirm it provides a tight fit to the wearer’s face. If there is not a tight fit, there could be leakage of airborne contaminants which will then be inhaled by the user. Even a slight leak can greatly reduce the protection afforded by the RPE, any facial hair such as beard stubble or moustache, or the wearing of spectacles, in the region where the RPE seals to the face will cause leakage and will result in failure of the fit test.
Conclusion
A survey has been conducted to understand the IOSH Middle East members perception on respiratory protection. In total, 136 responses have been received with the maximum of 33.1% from United Arab Emirates and 17.6% from Qatar. Most of them mentioned that they have been exposed to various form of dust, hydrocarbon fumes, hydrogen sulphide in the workplace. The survey indicates N95 Mask, SCABA, SABA, Cartridge mask, Triple layer cloth mask, FFP2, FFP3 and Escape sets have been widely used in the workplace. 86% HSE professionals strongly expressed adequate respiratory protection must put in practice in the workplace. 75% have stated that they are storing RPEs (Respiratory Protective Equipment) in a secured safe store area the remaining 25% seems to be not satisfied about RPE storage provision. 15% response received that they are not visual inspecting the RPE before using it. 32.4% participants have responded that they sensed a chemical smell after wearing cartridge filter mask. 25% of the responders mentioned that improvement required in proper selection, maintenance, cleaning and storage of RPEs. It is evident from this survey after an effective risk assessment, if appropriate respiratory protection equipment has been selected, respiratory hazards can be managed. But the survey points out improvements required in safe storage, cleaning of RPE, especially in medium scale industry and the appropriate training to be given about the inspection procedures.
References
De Matteis, S. et al. (2017) “Current and new challenges in occupational lung diseases,” European Respiratory Review, 26(146), p. 170080. Available at: https://doi.org/10.1183/16000617.0080-2017.
3 Categories of Respiratory Hazards in the Workplace (2021). Available at: https://www.esafety.com/3-categories-of-respiratory-hazards-in-the-workplace/.
Laboratory Safety Manual | Environment, Health and Safety (no date). Available at: https://ehs.cornell.edu/research-safety/chemical-safety/laboratory-safety-manual.
National Institute for Occupational Safety & Health | NIOSH | CDC. Available at: https://www.cdc.gov/niosh/.
Respiratory Protective Equipment (RPE). Available at: https://www.hseni.gov.uk/topic/respiratory-protective-equipment-rpe.
