Crystalline Silica and Cancer

Silica is a very common mineral. It is found in sand, quartz, stone, and concrete. Cutting, grinding, or drilling those materials releases a fine dust. Breathing that dust over time can scar the lungs and cause lung cancer. Controlling the dust is the key.

Crystalline silica is a natural mineral, and it makes up much of the earth's crust. The hazard is the very fine dust released when workers cut, grind, drill, or crush materials that contain it. That dust is called 'respirable' because the particles are small enough to reach deep into the lungs. Concrete, brick, tile, and engineered stone all contain silica.

Common ways people come into contact with it:

• Cutting, grinding, or drilling concrete, stone, brick, or tile.
• Working with engineered quartz countertops, sandblasting, or mining.
• Construction, masonry, foundry work, and quarrying.
• Breathing dust that hangs in the air in a poorly ventilated space.

Respirable crystalline silica causes lung cancer. It also causes silicosis, a serious scarring lung disease, and it raises the risk of other lung problems. Smoking pushes the lung cancer risk higher still.

The World Health Organization has a cancer agency, the International Agency for Research on Cancer (IARC). It places crystalline silica in Group 1, carcinogenic to humans. That is the strongest evidence category. It means there is enough evidence that the dust can cause cancer in people. The US National Toxicology Program agrees, listing crystalline silica in its Report on Carcinogens as known to be a human carcinogen.

The Group 1 listing is about the dust, not about you. It says respirable silica can cause cancer. Your own risk is a separate question, and it turns on how much dust you breathe and over how many years. A stonemason cutting quartz countertops all day is not in the same position as someone who once drilled a hole in a patio slab. Same mineral, same hazard, very different risk.

• Use wet-cutting methods and tools with dust collection, so the dust never gets airborne.
• Keep the air moving, and wear a properly fitted respirator when you need one.
• Follow the OSHA exposure limits for silica.
• Do not smoke.

Dust control is the whole game here. For where a single exposure sits in the bigger picture, see our overview of cancer prevention and what raises cancer risk.

Crystalline silica is a known human carcinogen (IARC Group 1). The risk lives in the dust, not in stone sitting still. If your work makes silica dust, the controls that keep it out of the air matter more than anything else you can do.