In brief
Crystalline silica is a dust released into the air when concrete, stone, brick, ceramics and moulding sand are cut, drilled or blasted, and its most dangerous fraction is invisible to the eye. The first way to reduce exposure is wet cutting and extraction at source; masks come after these. Health surveillance for silicosis is carried out with chest X-rays to ILO classification standards at intervals set by the workplace physician.
What is silica dust, and why is it an "invisible" risk?
Silica dust is the fine dust released into the air when a material containing quartz is cut, drilled, ground or crushed. The Regulation on Dust Control defines crystalline silicon dioxide (SiO₂) as quartz, tridymite and cristobalite (Art. 4). Sand, granite, sandstone, concrete, mortar, brick, ceramics and the moulding sand used in foundries contain quartz; in engineered (composite) stone worktops this proportion can be very high.
The problem is that the most dangerous fraction cannot be seen. The coarse particles of the grey cloud rising during cutting settle quickly; the respirable particles that can reach the deepest parts of the lungs, however, can remain suspended in the air for a long time. You cannot conclude that exposure has ended because the area "looks clean". Crystalline silica exposure is therefore managed on the basis of measurement and health surveillance, not appearance.
The International Agency for Research on Cancer (IARC) classifies quartz and cristobalite dust as carcinogenic to humans (Group 1). This article explains in which jobs crystalline silica arises, how it is controlled by wet cutting and extraction, and how health surveillance for silicosis is planned. For the general obligations of the regulation and the limit value calculation, see our article on the Regulation on Dust Control.
In which jobs does crystalline silica exposure arise?
The table below shows the jobs in construction and related sectors where silica dust is most often produced, and the control to apply first in each.
| Job | Where does the silica come from? | Priority control |
|---|---|---|
| Cutting concrete and asphalt, cutting joints and chases | Concrete, aggregate | Water-fed cutting machine; extraction at the cutting point |
| Drilling concrete, breaking with a breaker | Concrete, mortar | Dust shroud on the drill and an industrial vacuum with filter |
| Chasing walls, scraping plaster | Mortar, brick | Wall chaser connected to extraction |
| Cutting ceramics, marble and granite | Stone and ceramics | Wet cutting bench; collecting waste sludge before it dries |
| Engineered stone worktop manufacture | Composite stone | Wet processing, bench with extraction, segregated work area |
| Abrasive blasting | Abrasive and surface | Silica-free abrasive, enclosed cabinet, air-fed protective equipment |
| Moulding sand preparation and fettling in foundries | Moulding sand | Enclosed system, local exhaust, wet cleaning |
| Site and workshop cleaning | Dust settled on the floor | Vacuum or wet method instead of dry sweeping |
What the jobs in the table have in common is the mechanical breaking up of the material. An intact concrete block or a sealed bag of sand does not create dust on its own; cutting, drilling, breaking, blasting and dry sweeping do. In the risk assessment, naming the agent and the job together, such as "quartz-containing dust from concrete cutting" rather than simply "dust", targets both the measures and health surveillance correctly.
Stone cutting dust does not affect only the person doing the cutting. If dry cutting is done in an enclosed area, an employee plastering, carrying materials or installing services in the same section breathes the same air. Because jobs overlap on a construction site, the timing and location of dust-producing work are also part of planning; see our construction site OHS checklist.
Silicosis risk: how does the disease develop?
Silicosis is a pneumoconiosis that develops when inhaled crystalline silica builds up in the lungs and forms permanent scar tissue (fibrosis). It usually progresses silently over the years; by the time shortness of breath, coughing and sputum appear, the damage is generally established. With very heavy exposure, it can appear in a shorter time. Silica exposure is also associated with lung cancer and chronic lung diseases; silicosis can also occur together with tuberculosis.
In the list of occupational diseases, silicosis and silicotuberculosis are in group C, with a liability period of 10 years (Annex 2 of the Regulation on Procedures for Determining the Rate of Loss of Working Capacity and Earning Capacity). The jobs listed under this heading include cutting and polishing siliceous stone, fettling and blasting in foundries using sand, and removing rust with abrasive blasters. In other words, even if an employee is diagnosed years after leaving the job, the disease may be linked to that work. We explain how to read the list in our article on the list of occupational diseases.
Wet cutting and extraction at source: the order of controls
Art. 5 of the regulation sets an order for measures: first substitution, then preventing the risk at source and collective protection, appropriate engineering methods and adequate fresh air; if these are insufficient, personal protective equipment suited to the nature of the dust. Art. 9 also requires dust formation to be prevented, and dust to be eliminated or suppressed at source. On site, this order is applied as follows:
- Substitution: Choose a silica-free abrasive for blasting; where possible, use pieces prepared to size instead of cutting on site.
- Wet cutting: Use the system that delivers water to the cutting point on cutting and grinding machines. If a dusty cloud comes from the cut, the water is insufficient.
- Extraction at source: On drills, wall chasers and grinders, connect the dust shroud on the tool to an industrial vacuum with a high-efficiency filter (class H). As the filter fills, suction drops; write filter replacement into the instruction too.
- Work organisation: Schedule dusty work in enclosed areas for times when other teams are not present, segregate the area and increase ventilation.
- Cleaning: Do not clean by dry sweeping or with compressed air; use a vacuum or wet method. Collect the sludge left from wet cutting before it dries; dried sludge turns back into dust.
- Respiratory protection: If exposure continues despite these measures, use a mask with a protection level suited to the measurement result. For mask class and face fit, see our article on choosing a dust mask.
Measurement: how do you know the exposure?
Art. 8 of the regulation requires dust measurements to be carried out at periodic intervals determined by the risk assessment, repeated when conditions affecting exposure change, and the results evaluated against the limit values in Annex 1. Measurements to be used in inspections are carried out by laboratories holding a preliminary qualification or qualification certificate from the Directorate General. Under Art. 9, measurement is repeated after the measures are taken; work is permitted when the dust concentration is found to comply with the limit value.
When reading a silica measurement report, look at three points:
- Are the respirable dust and crystalline silica proportion given separately? Even if total dust appears low, the respirable fraction containing silica may exceed the limit.
- In which job and in whose breathing zone was the measurement taken? The exposure of the operator doing the cutting and the general air in the area are not the same thing.
- Was the measurement day realistic? A day on which cutting lasted half a day does not represent a day of full-shift cutting.
We plan crystalline silica measurement with accredited laboratories and enter the results into the risk assessment. You can find in which situations measurement becomes mandatory in our article on workplaces requiring workplace atmosphere measurements.
How is health surveillance for silicosis planned?
Art. 10–14 of the Regulation on Dust Control set special provisions on top of the general health surveillance rules for employees exposed to dust. The table summarises the plan:
| Step | What is done? | Basis |
|---|---|---|
| Pre-employment | Pre-employment examination and chest X-ray to ILO classification standards | Art. 10, 11 |
| Periodic monitoring | At a frequency set by the physician according to the risk assessment, measurement results and type of dust | Art. 10, 11 |
| Reading the X-ray | For dusts containing quartz, X-rays are assessed by a reader trained in ILO classification | Art. 11 |
| Result | Category 0: follow-up with periodic examinations; Category 1 and above: referral to a health service provider authorised by the SGK (Social Security Institution) | Art. 12 |
| After diagnosis | The employer provides the working conditions stated in the health institution's report | Art. 13 |
| Records | Job, length of service, measurement results and health files; kept for 15 years from leaving employment unless a special provision applies | Art. 14 |
The general periodic examination intervals also apply: at least every 3 years in the hazardous class and every year in the very hazardous class. For example, site preparation (43.12.00) is in the very hazardous class. The physician may shorten this interval; the physician also determines the frequency of tests such as lung function tests according to exposure. Based on the results, the workplace physician may recommend that the employee not be employed in work involving dust exposure, and may also determine how long monitoring will continue after exposure ends (Art. 10). This is the natural consequence of silicosis being able to appear late.
We plan chest X-rays, lung function tests and other investigations with authorised health institutions, and enter the results into both the health file and the risk assessment. For general examination intervals, see our article on periodic examinations and tests.
Frequently Asked Questions
If we cut wet, is a mask still needed?
Wet cutting significantly reduces dust but may not be sufficient for every job. Measurement decides: if exposure does not stay below the limit value after the measures, suitable respiratory protection is used. For long cuts in enclosed areas, a mask is usually kept as a complementary measure.
How often is a chest X-ray taken for silica dust?
The regulation does not set a fixed interval; the workplace physician determines it according to the risk assessment, measurement results and type of dust. For dusts containing quartz, X-rays are assessed by a reader trained in ILO classification.
Is there a difference between quartz dust and ordinary construction dust?
Yes. Dusts that do not contain silica can also be harmful; however, respirable dust containing quartz can cause silicosis and lung cancer. This is why the measurement report looks at respirable dust and the crystalline silica proportion as well as total dust.
Can an employee diagnosed with silicosis continue in the same job?
The employer is obliged to provide the working conditions stated in the report of the health institution that made the diagnosis (Art. 13). The employee may need to be moved to work where they will not be exposed to dust; the decision is made according to the report and the workplace physician's assessment.
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.