In brief
Chest X-rays of employees in dusty work are taken and read to the standard of the ILO International Classification of Radiographs of Pneumoconioses. Under the Dust Control Regulation, in workplaces with dusts containing asbestos and quartz, the X-ray is assessed by a physician who has received ILO reader training; category 0 results are followed up with periodic examinations, and for category 1 and above the employee is referred to a healthcare provider authorised by the Social Security Institution (SGK).
What is an ILO chest X-ray, and how does it differ from an ordinary film?
The chest film requested at the periodic examination of an employee in dusty work, such as foundry sand, quarrying, ceramic slip or concrete cutting, is not assessed for the same purpose as a chest X-ray taken in an emergency department. An ILO chest X-ray is a film taken and read according to an international classification that lets every reader record the traces dust leaves in the lungs in the same language. The aim is to make films taken over the years comparable with each other and to catch pneumoconiosis before symptoms begin.
The Dust Control Regulation defines a standard chest radiograph as follows: a chest radiograph of at least 35×35 cm, or a digital chest radiograph, that can be assessed according to the criteria of the ILO International Classification of Radiographs of Pneumoconioses (Art. 3). The classification is designed only for posteroanterior (PA) chest radiographs.
We described pneumoconiosis itself, its types and symptoms in our article on pneumoconiosis: lung disease in dusty work. This article focuses on how the X-ray is read and what the result means.
What is the ILO classification? The components of a reading
The ILO International Classification of Radiographs of Pneumoconioses is used to describe and record systematically the radiological changes in the chest caused by inhaling dust. It is not a diagnostic tool but a recording language: the reader compares the film with standard films and writes down what they see in codes. The current edition was published in 2022 and renewed the set of standard images with digitally acquired images; the ILO states that JPEG images intended for teaching should not be used for classification, and that classification should be done with DICOM images on diagnostic monitors.
| Component | Codes | What does it describe? |
|---|---|---|
| Technical quality | 1–4 | Readability of the film; 4 is unacceptable and the film is repeated |
| Small opacities: shape and size | Rounded: p, q, r · Irregular: s, t, u | p/s up to 1.5 mm; q/t 1.5–3 mm; r/u 3–10 mm |
| Small opacities: profusion | 12 steps from 0/- to 3/+ | How dense the shadows are |
| Affected zones | Upper, middle, lower in each lung | Distribution of the change |
| Large opacities | A, B, C | Combined size of shadows larger than 1 cm |
| Pleura | Plaques, diffuse thickening, calcification | Particularly important in asbestos exposure |
| Symbols | Such as es, ax, tb, em | Additional findings (e.g. es: eggshell calcification of lymph nodes) |
For large opacities, A denotes one or more shadows whose combined size does not exceed 5 cm; B those exceeding 5 cm but not the area of the right upper lung zone; and C those exceeding this area.
Category chart: from 0/0 to 3/+
The profusion of small opacities is written in the form "major/alternative". The number before the slash shows the category the reader has decided on, and the number after it shows the alternative category they seriously considered. For example, 1/0 means "category 1, but I also thought it could be 0"; 0/1 means "category 0, but I also considered the possibility of 1".
The ILO International Pneumoconiosis Assessment Category Chart in Annex 3 of the Dust Control Regulation groups these 12 steps into four categories:
| Category | Sub-steps |
|---|---|
| 0 | 0/-, 0/0, 0/1 |
| I | 1/0, 1/1, 1/2 |
| II | 2/1, 2/2, 2/3 |
| III | 3/2, 3/3, 3/+ |
In practice the most debated result is 0/1: according to the chart it is category 0, but the reader has seen something. This employee's film should be assessed side by side with the previous film at the next examination; the workplace physician should shorten the repeat interval if necessary.
The pneumoconiosis reader: who can assess the X-ray?
The Regulation defines a "reader" as a physician who has received training in the ILO International Classification of Radiographs of Pneumoconioses (Art. 3). Reader training is organised by the Occupational Health and Safety Institute, and successful physicians receive a certificate (Art. 16). Who reads the film depends on the type of dust at the workplace (Art. 11):
- Dusts containing asbestos and quartz: X-rays are assessed by a reader according to the ILO classification. If readers' results differ, a joint assessment is made and the final result is notified to the employer in writing.
- Other dusts: The workplace physician assesses the X-ray, taking into account the characteristics of the dust; when necessary, it is sent to a reader for further assessment.
- List of readers: Available from the website of the Directorate General of Occupational Health and Safety or the Occupational Health and Safety Institute.
Because crystalline silica is common in foundries, glass, ceramics, stone processing and construction, many workplaces in Bursa and the surrounding provinces are in the first group. For sources of silica, see our article on crystalline silica dust.
When is a chest film taken in dusty work?
The Regulation does not set a fixed interval in years. X-rays are taken in the situations listed in Art. 15 of Law No. 6331 (pre-employment, change of job, request to return to work, periodic examination) and at the frequency set by the workplace physician (Art. 11/1). In workplaces where dusts containing asbestos and quartz may be present, the physician sets this frequency taking into account the risk assessment, dust measurement results and the employee's health (Art. 11/2).
In practice, three rules make the job easier:
- Baseline X-ray at pre-employment: This is the first film against which later films are compared. Without a baseline film at pre-employment, it becomes debatable years later whether a change began at the workplace.
- Keep previous films: The reader must be able to compare the new film with the old one. Digital images need to be accessible in the personal health file.
- Link to measurements: When dust measurement results rise or the process changes, the physician reassesses the test interval. For measurement methods, see our article on dust measurement and respirable dust.
The X-ray alone is not enough; it is interpreted together with a lung function test, which shows changes in lung function.
How does the result affect the fitness-for-work decision?
Art. 12 of the Regulation sets out two paths for the employer who receives the reader's final report:
- Category 0: The employee is followed up with periodic examinations.
- Category 1 and above: The employee is referred to healthcare providers authorised by the SGK. The diagnosis of occupational disease is made there.
Based on examination and test results, the workplace physician determines all kinds of measures, including not employing the employee in work involving dust exposure (Art. 10/1). Once a diagnosis is made, the employer is obliged to provide the working conditions stated in the authorised healthcare provider's report (Art. 13). For how to apply a restricted fitness report at the workplace, see our article on restricted or unfit reports.
On the SGK side, Art. 20 of the Regulation on the Procedures for Determining Loss of Working Capacity and Earning Capacity requires a total of at least three years of work in dusty workplaces capable of causing pneumoconiosis for pneumoconiosis to be recognised as an occupational disease, and states that pneumoconiosis assessments are made taking ILO standards into account. A film taken outside the standard or not read according to the ILO therefore weakens both the employee's rights and the employer's defence.
Steps for the employer
- Clarify the type of dust at the workplace (asbestos, quartz, other) in the risk assessment; the reader requirement depends on it.
- Have the X-ray taken PA, at least 35×35 cm or to the digital standard; have films of poor technical quality repeated.
- For asbestos and quartz exposure, add the reader's report to the file.
- Do not delay referral for category 1 and above results; adjust the employee's dust exposure immediately in line with the physician's recommendation.
- Keep films and reports in the personal health file in a way that allows comparison years later.
We plan tests with authorised laboratories and healthcare providers within the scope set by the workplace physician. For service details see our health surveillance page, for dust sources in construction work our construction sector page, and to track examination dates our OHS calendar tool.
Frequently Asked Questions
Should an ILO standard chest film be taken every year?
The legislation does not give a fixed interval. X-rays are taken at pre-employment, on a change of job and at the frequency set by the workplace physician based on the risk assessment, dust measurements and the employee's health.
Can any radiologist read the X-ray according to the ILO?
In workplaces with dusts containing asbestos and quartz, the X-ray is assessed by a certified physician who has received ILO reader training. For other dusts, the workplace physician carries out the assessment and sends it to a reader if necessary.
What does a 0/1 result mean?
The employee is in category 0, but the reader also considered the possibility of category 1. The employee is followed up with periodic examinations; the workplace physician assesses the next film by comparing it with the previous one and shortens the interval if necessary.
What is done for an employee with a category 1 result?
The Dust Control Regulation provides for the employee to be referred to a healthcare provider authorised by the SGK in this case. The employer provides the working conditions recommended by the physician and stated in the authorised provider's report; if necessary, the employee is assigned to work without dust exposure.
An exposure-based test plan, pre-employment and periodic examinations, confidential health files and an examination schedule tracked per person.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.