Health and Safety

Taking care with materials, equipment and work procedures and dealing with hazards.

Silica dust

Silica dust is produced when polishing and grinding concrete, and also when cutting concrete or masonry, or drilling, crushing and cutting some types of fibre-cement board. It can also be produced when cutting or grinding engineered kitchen benchtops that have a high silica content. Breathing in fine silica dust over prolonged periods can cause shortness of breath, coughing and, in extreme cases, serious lung disease. Research shows it is a risk for New Zealand builders, with many being exposed to silica dust with little knowledge about it.

A report into this commissioned by WorkSafe New Zealand was released in 2015. The main findings were:

  • a lack of knowledge of the risk of silica dust
  • a lack of efficient dust suppression methods
  • a large number of construction workers not using respiratory protection.

Sample testing of workers performing selected ‘at risk’ tasks showed that they are being exposed to levels of silica dust which exceed national and international standards.

A serious problem has emerged in Australia in the industry producing natural and engineered stone benchtops. Very high short-term exposures to silica dust have been found to cause the incurable illness silicosis to develop rapidly, a condition known as acute silicosis. This can lead to disability and can be fatal.

Protection required

Exposure to silica dust should be eliminated, isolated or minimised. Dust control is top priority:

  • Wet any dust before it can become airborne, and frequently clean work areas and equipment with water.
  • Never sweep up dry dust. Use a vacuum cleaner with a HEPA filter that takes particles out of the air.
  • When buying equipment for cutting and grinding, look for dust control features such as a dust collection device or a water system to the blade. Then make sure those operating the equipment use these features.

The appropriate masks should always be available. Where dust levels are low, disposable masks may be sufficient. Make sure they have two straps and fit securely around the face. Half-face or full-face masks will be required where dust levels are greater.

Make sure dusty clothes are cleaned and they do not carry dust into vehicles or homes.


Updated: 27 November 2019