Occupational disease

What is an occupational disease?

An occupational disease is a disease caused by a working environment risk factor or the nature of the work included in the list of occupational diseases.

A medical examination at an occupational health doctor will help diagnose the disease. A doctor who suspects an employee of an occupational disease will refer them to an occupational health doctor. An occupational disease is diagnosed by an occupational health doctor, who determines the worker's state of health and collects data on their current and previous working conditions and the nature of the work. The occupational health doctor shall notify the employer, the Labour Inspectorate and the doctor who referred the employee to the occupational health doctor in writing of the occupational disease.

The list of occupational diseases established by a regulation of the Minister of Social Affairs sets out the causes of occupational skin diseases and tumours and the list of respiratory occupational diseases and tumours. The regulation also contains a list of chemical hazards in the working environment that may cause an occupational disease and occupational diseases caused by physical and physiological hazards in the working environment.

Allergens

What allergens are a source of threat at work?

There is an official list of occupational diseases in the Republic of Estonia, which places allergens in the list of causes of occupational diseases. Subsection 5 (2) of the Regulation expressly states that the list also includes occupational skin diseases which have arisen as a result of scientifically proven allergenic or irritating substances.

About 10% of all registered occupational diseases are caused by hazardous chemicals in the working environment.

An example from life itself – how about so little exposure and that much trouble?

Years ago, the Labour Inspectorate investigated a case in which an employee was diagnosed with an occupational disease, allergic contact dermatitis, in a small construction establishment. The worker had received it from exposure to epoxy resins.

The employer could not understand that an illness such as an allergy could also be an occupational disease and that the illness could be caused by the materials used in their establishment. According to the employer, the employee's exposure to epoxy resins was short-lived (estimated at two months) and during that time the employee could not possibly develop permanent damage! Epoxy resins are widely used as floor covering materials and the manager of the works was a highly experienced specialist who has gained knowledge of working with these materials outside Estonia. In the safety instructions prepared for the work, the employer had not considered the work with epoxy resins to be harmful and explicitly wrote that working with these floor covering materials (resins) was not harmful to health and did not prescribe any special protective measures or protective clothing. The work was routine and the protective equipment used was rather standard.

Unfortunately, the employer had not read the very important documents, which were the safety data sheets for the chemicals used. They clearly stated that these were irritating and hypersensitive chemicals and provided adequate respiratory protection as well as epoxy-resistant work clothes and work gloves as safety precautions.

In the light of this case, professional literature was also thoroughly examined to explain to the employer why the employee became ill.

• Allergic contact dermatitis is caused by many chemicals that are safe in themselves.
• Depending on the substance, symptoms may occur less than an hour or a few days after contact.
• In case of allergic contact dermatitis, dermatitis can sometimes be seen on the same day after contact. It is typical that the reaction becomes stronger within 4–5 days.
• The development of allergies is facilitated by external stress.
• Epoxy compounds are also the cause of allergic contact dermatitis.
• Epoxy compounds are substances that cause an early allergic contact reaction with symptoms 1–2 days after contact. In skin tests, epoxy resin has caused early contact reaction and anaphylactic symptoms. Epoxy resins are placed in the group of strong sensitisers.

(‘Allergology’, edited by Maie Laaniste, AS Medicina 2002).

• Exposure to epoxy resin until contact allergy develops can be quite short (less than one month up to a few years).
• Any single and accidental exposure to an allergen (epoxy resin) can trigger a hypersensitivity reaction.
• Epoxy compounds can cause contact dermatitis by direct contact with the skin, but also by airborne transmission. Typical areas involved are the fingers, the spaces between the fingers, the arms up to the wrists and the eyelids.

(‘Handbook of Occupational Dermatology’, L. Kanerva, P. Elsner, J. E. Wahlberg, H. I. Maibach, Springer 2000).

However, the lesson for the case described above could be this: chemicals that initially seem safe can also cause damage to health, and in particular the chemicals used need to be studied in more detail.

In fact, the epoxy resins used are not safe at all and are well known in the world of allergies.

What is an allergy?

Dr. Kaja Julge writes on the portal kliinik.ee that allergy means a change in the reactivity of the body's immune system to a factor to which the immune system did not react on initial contact. Thus, it is an ‘alternative’ reaction, an unusual sensitivity or hypersensitivity to a substance or factor (antigen), which in this case is called an allergen.

Hypersensitivity can be caused by, for example, foodstuffs, medicines, inhaled particles, insecticides, animal hair, etc. An allergy is primarily a hypersensitivity reaction of the immune system, i.e. protection, but in this case too strong protection against some completely harmless or relatively safe factor. Another characteristic of allergy is specificity, i.e. an allergic reaction in a particular person only to certain allergens, the amount of which may increase over time.

How to determine if an employee is exposed to allergens?

As can be seen from the above quotation, a wide variety of substances can be allergens. In the working environment, these are mostly chemicals, but there may also be allergens of biological origin.

Whether or not one or the other chemical may cause hypersensitivity, the necessary information should be sought. The primary source of information is the packaging of the chemical, provided that the chemical is bottled in the original packaging and not re-poured into, for example, a lemonade bottle.

The labelling of hazardous chemicals that cause allergies distinguishes between respiratory or skin sensitization.

The label element for respiratory sensitisation is the torso in the diamond lined with red.

The skin sensitisation marker element is an exclamation mark in a diamond bordered with red.

Therefore, the feeling of danger must increase if you see these two hazard pictograms on the packaging of the chemical.

Next, of course, it is necessary to look at the hazard statement used. Hazard statements are given as a combination of the letter H and a three-digit number, and in the explanatory text we find the words ‘allergy’ and ‘allergic’.

Allergens are used in our working environment, what to do next?

Further instructions on how to work safely with one or another chemical can be found in the chemical safety data sheet. It specifies the working environment (for example, whether working with the chemical requires separate exhaust ventilation or simply a well-ventilated room), the personal protective equipment to be used and the appropriate method of storing the chemical.

What are the most common allergens in the working environment?

There are 100,000 to 300,000 chemicals in use worldwide, and nearly a thousand new chemicals are introduced each year. Thus, the amount of chemicals used increases every year. Out of all the chemicals in use, 10–25% can also be allergens.

The best known substances that cause respiratory sensitisation are various adhesives, paints, resins, surface protection products, pharmaceuticals, food supplements, cleaning agents, welding fumes and metals, hair dyes, bleaching agents, textile chemicals, and textile fibres.

However, skin sensitisers include various metals (nickel, chromium, cobalt), resins, plastics (wood rosin, epoxy resins, isocyanates, acrylates, formaldehyde), dyes (paraphenylenediamine, fabric dyes), disinfectants, fragrances, rubber chemicals, solvents, film preservatives.

How to avoid adverse effects on worker health?

Measures to reduce health risks are listed in sufficient detail in a government regulation on occupational health and safety requirements for the use of hazardous chemicals. They are universal for all chemicals:

The primary task is to try to reduce risks by optimising the work process, and in particular, priority should be given to activities that could be called collective defence:

• replacing technology based on the use of hazardous chemicals with safer ones;
• replacing a hazardous chemical with a safer one;
• reducing the number of workers exposed to hazardous chemicals;
• shortening the working time with hazardous chemicals;
• reducing the amount of hazardous chemicals in the workplace.

However, if the above measures do not provide adequate protection and are not sufficiently effective, the risks must also be reduced by better work organisation, moving from general to the individual:

• use of the right work methods;
• use of equipment and technologies to ensure the safety of workers;
• use of appropriate tools and materials;
• regular technical inspection and maintenance of equipment.

What to emphasise in conclusion?

• Hazards in the working environment must not be ignored! Even a seemingly (initially) safe substance can cause a lot of trouble.
• Physical load in the working environment also promotes the development of allergies.
• In most cases, dangerous chemicals have the necessary information (provided that they are not produced anywhere in third countries to which European Union directives do not apply).
• Every chemical is a poison. The amount of poison depends on the amount of the chemical, but sometimes a very small amount and short-term exposure are sufficient.

Author: Silja Soon, Head of the Occupational Health Service of the Labour Inspectorate