Silica dust

Silica is a very abundant mineral in earth’s surface. Although, actually, this nomenclature encloses, not only a type mineral, but a group of them which are composed of silicon and oxygen.

They can present various different forms, being the most common one the crystalline state.

The most common ones are quartz, cristobalite and tridymite, which are often referred to as types of “free” crystalline silica because the crystalline silica is not chemically combined.

Among them, quartz is by far the most common form of silica, being very present naturally in nature.

For their part, cristobalite and tridymite are not abun- dant in nature, although it is relatively frequent to find them in industrial processes.

For example, cristobalite is obtained when quartz is heated.

Furthermore, silica is present in many materials com- monly used on construction, including soil, sand, concrete, masonry, rock, granite, and landscaping materials.

So, the term ‘silica dust’ is referred to dust created by cutting, grinding, drilling or otherwise disturbing these materials can contain crystalline silica particles.

These dust particles are very small, so much so that they are imperceptible to the human eye.

Why is silica dust a hazardous substance?

When inhaled into the lungs, silica dust is very harm- ful, as it is 100 times smaller than a grain of sand, and it can be inhaled without knowing it.

Exposure to silica dust can lead to the development of lung cancer, silicosis (an irreversible scarring and stiffening of the lungs), kidney disease and chronic obstructive pulmonary disease.

In this regard, it must be pointed out that cancer risk increases with long-term or repeated high-level exposure.

It is known that all around the world a lot of people develop lung cancer each year as a result of past exposure to this substance at work. Not all exposed workers will develop cancer.

However, it must be noted that exposure to pure crys- talline silica is extremely rare.

The silica dust inhaled is usually composed of a mix- ture of crystalline silica and other materials.

For that matter, the response of an individual is likely to depend on: the nature and crystalline silica content of the dust, the dust fraction, the extent and nature of personal exposure, the personal physiological charac- teristics and smoking habits.

Where can silica dust be found?

In nature, silica dust is found in some stone, rock, sand, gravel and clay. The most common form is quartz.

On manufactured products and materials, silica-dust can mainly be found in:

  • Silica containing composites
  • Sandstone, gritstone, quartzite, flint
  • Bricks
  • Tiles
  • Slate
  • Granite
  • Ironstone
  • Basalt, dolerite
  • Concrete and mortar
  • Some plastic materials

Taking these into account, it is often present in the following industries:

  • Quarrying
  • Mining
  • Mineral processing
  • Slate working
  • Stone crushing and dressing
  • Foundry work
  • Brick and tile making
  • Construction work, including work with stone, con- crete, brick and some insulation boards,
  • Tunnelling
  • Building restoration
  • Pottery and ceramic industries


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This article can be found in the 2021 edition of the document. Find the full publication here: