Silica Dust in Dry Grinding: Health Risk with Granite and Quartz

When the edge of a kitchen countertop is sanded dry on site, or a granite floor is ground without water, part of the dust that rises is plain to see: a gray layer settling on the table, the cabinets, the windowsill. The truly dangerous part is the one you cannot see. When quartz-containing materials such as granite, quartz composite and quartzite are processed dry, they release very fine crystalline silica particles that, once inhaled, can travel down to the deepest parts of the lungs. In this article we explain where silica dust comes from, which surfaces carry a higher risk, why it should be taken seriously from a health standpoint, and which precautions can be taken for both workers and households. For personal health questions, always consult a physician, and for workplace practices, an occupational safety specialist.

In short: Dry grinding, cutting and sanding of quartz-containing stones produces respirable crystalline silica dust; with long-term exposure, this dust is associated with permanent lung diseases such as silicosis. The risk is highest with quartz composite and granite, and lowest with calcitic marble. The basis of the solution is to bind the dust with water at the source and to use dust extraction with a suitable filter; a mask is used in addition to these, not instead of them.

What Is Silica, and Which Dust Is Dangerous?

Silica is a compound of silicon and oxygen and is one of the most abundant substances in the Earth's crust. Its most common crystalline form is quartz. Sand, granite, quartzite, sandstone and quartz composite countertops contain significant amounts of quartz. These materials pose no hazard while they stay intact; everyday use of a finished granite countertop or an installed floor does not produce silica dust. The risk begins when the material is cut, ground, sanded or broken, that is, when particles become airborne.

Not all of this dust is equally dangerous. Coarse particles are trapped in the nose and throat and settle to the floor quickly. The real problem is the portion that is too fine to be seen with the naked eye, known as "respirable" dust. These particles stay suspended in the air for a long time, drift between rooms, and when inhaled reach the air sacs of the lungs. So the fact that an environment does not look dusty does not mean it contains no respirable silica.

An example helps show how small the quantities involved are. For respirable crystalline silica in workplaces, OSHA sets a permissible exposure limit of 50 micrograms per cubic meter of air as an eight-hour average; at 25 micrograms, additional measurement and monitoring obligations begin. A microgram is one millionth of a gram. In other words, the amounts considered significant for health are far below a visible cloud of dust. In Turkey, dust exposure in workplaces is also regulated by the relevant occupational health and safety regulations; for binding values, consult the current legislation and an occupational safety specialist.

How Much Risk on Which Surface?

Silica risk depends directly on how much quartz the processed material contains. This share varies by stone type, and even between different quarries for the same type. Publications by OSHA, the US occupational safety agency, and NIOSH, its research institute, generally give crystalline silica contents of 10 to 45 percent for granite, and up to 50 percent in some sources. In quartz composite countertops, the share is above 90 percent in most products. For this reason, quartz composite stands out as the highest-risk material for cutting and edge finishing.

The main mineral of marble is calcite, and pure calcitic marble contains very little quartz. This means the silica risk in grinding marble is markedly lower than with granite and quartz composite. However, some marbles may contain quartz and other silicate minerals in their veins or structure; moreover, any kind of fine stone dust is harmful to the respiratory tract. For the exact share, check the manufacturer's information or the safety data sheet of the material.

The table below gives a general summary of the silica risk on common surfaces and points to watch for in dry processing:

Health Effects: Why Take It Seriously?

Long-term inhalation of respirable crystalline silica can cause a permanent lung disease called silicosis. In silicosis, lung tissue gradually hardens and breathing becomes difficult; the disease is progressive and irreversible. The International Agency for Research on Cancer classifies crystalline silica among the substances carcinogenic to humans. Silica exposure is also linked to chronic lung diseases and other health problems. These diseases usually develop over years; a person may not feel the effect of the dust they are exposed to today for a long time.

Turkey experienced how severe this risk can be through denim sandblasting. Many young workers developed silicosis in workshops where sand was blasted onto denim fabric, and in 2009 the Ministry of Health banned the use of silica-containing materials in this process. In recent years, silicosis cases in workshops processing quartz composite countertops have also drawn attention worldwide; Australia largely banned the use of engineered stone as of 1 July 2024. These examples show that uncontrolled dry processing is not a matter of preference but a serious health risk.

Why Are Dry Grinding and Dry Cutting Risky?

In stonework, most of the dust is generated in three situations: dry cutting, dry edge finishing and dry grinding. Cutting a countertop to size on site with an angle grinder and no water, drilling a sink cutout dry, or smoothing an edge with dry sandpaper produces dense dust in a short time. Grinding a granite floor without water, on the other hand, is a continuous dust source spreading over a wide area.

There are situations where the dry method is tempting: places where using water is difficult, the risk of leaking to the floor below, wooden and plaster surroundings, or small jobs that must be finished quickly. In these cases the dry method is not banned outright, but it should only be considered together with an extraction system that captures the dust at the source. We made a general comparison of the wet and dry methods in terms of dust, water and noise in the article wet and dry grinding as well.

Wet Method and Dust Extraction

The most effective measure against silica dust is keeping the dust from becoming airborne at all. In wet cutting and wet grinding, water turns the dust into slurry at the point where the abrasive touches the stone. This slurry does not produce dust while wet; however, because it can turn back into dust once it dries, it should be collected at frequent intervals and removed from the area before it dries. Using water-fed tools for countertop cutting and drilling on site means far less dust than dry cutting.

In jobs where dry work is unavoidable, the dust should be captured by a shroud right next to the tool and drawn into an industrial dust extractor. This extractor should have a filter in a class that can retain fine dust, and the filter should be cleaned and replaced regularly. An ordinary household vacuum cleaner is not suitable for this job; it cannot retain fine dust and may blow it back into the room with its exhaust air. The compatibility of the machine and the extraction system is among the first things to ask about before the job. We explained how to choose grinding equipment in the article choosing a grinding machine as well.

Precautions for Workers

Precautions against silica dust in workplaces fall under occupational health and safety legislation and are determined by the employer's risk assessment. The general order of these precautions is to first reduce dust at the source, then control the environment, and finally complete the protection with personal protective equipment. A mask is no substitute for the wet method and extraction; it is the last line of defense alongside them.

The main precautions for teams working with stone are as follows:

• Suitable respirator: Choose a mask designed for dust and in a protection class suited to the job, and check that it fits the face well; a beard can break the mask's seal.
• Clean work clothes: Do not go home in dusty work clothes, do not shake them out, and wash them separately from the family laundry; otherwise the dust is carried into the home.
• Do not use compressed air: Cleaning dust off clothing or the floor with compressed air throws it back into the air; vacuuming or wet wiping should be preferred.
• No eating or drinking in the work area: Eating, drinking and smoking in an area with dust lead to the dust being swallowed and carried to the face by hand.
• Health surveillance: Having employees who work with stone regularly monitored by an occupational physician helps detect possible effects early.

Precautions for Household Members and the Surroundings

In a countertop or floor job done at home, the people most often overlooked are those who live in the house. Children, elderly people and people with respiratory problems should not be at home during dry processing and immediately afterwards. The room where the work will be done should be closed off as much as possible, gaps around doors should be sealed with plastic sheeting and tape, and air conditioning and central ventilation should be kept off while the work is under way; otherwise fine dust spreads throughout the whole house.

Cleaning after the job is finished is also important. If the dust is swept dry with a broom or brush, the fine particles that have settled rise into the air again. Instead, you should vacuum with a filtered vacuum cleaner that can capture fine dust, and then wipe the surfaces with a damp cloth. Curtains, upholstered furniture and the tops of cabinets should not be forgotten either. Pets should also be kept in another room or outside the house during the work, and their water and food bowls should be moved away from the work area. For a countertop correction that requires dry processing, the safest way is, if possible, to remove the piece and process it in the workshop under suitable conditions. We have also covered the problems seen with quartz composite countertops in the quartz countertop article separately.

Questions to Ask When Hiring

When talking to a company about on-site work on granite, quartz composite or quartzite, a few questions will help you understand how the work will be done. If the answers to these questions are not clear, the method of the work needs to be discussed again:

1. Method: Will the work be done wet or dry? If it will be done dry, the reason and how the dust will be captured must be explained clearly.
2. Extraction system: What are the filter class and capacity of the dust extractor that will be connected to the tools, and will a household vacuum cleaner or an industrial unit be used?
3. Cutting location: Will cutting to size and drilling holes be done on site or in the workshop? Work that can be done in the workshop should not be done at home.
4. Protection and cleaning: You should be told how the work room will be separated off, which method will be used for cleaning at the end of the job, and when household members can return.

With wet grinding, the silica risk is markedly reduced; however, the wet method also has its own safety issues. We explained the precautions related to electricity, noise and chemicals in the article on occupational safety in grinding . To plan the method of the work to be done on your granite or quartz surface together, you can send us the type of surface and the work to be done through the service request form