ALL YOU NEED TO KNOW: Silica & the effect on you


Crystalline silica also referred to as silica/quartz is a very common mineral. Its can be present in soil, sand, granite, concrete, stone/rock, clay, artificial stone, glass, some plastic materials & many other building materials commonly used with everyday construction.
Silica is the second most common mineral in the earth’s crust & has been used in the construction industry since the early 1700’s.
When these construction materials are worked on, silica tends to be released in an extremely fine dust. Often these dust particles are 100 times smaller than a grain of sand. Construction workers could be exposed to the tiny particles of silica when cutting, drilling, sanding, demolishing or mining materials that contain silica.
This list of products may contain silica:

  • Asphalt
  • Brick
  • Cement
  • Concrete
  • Fibre cement products (cladding panels)
  • Grout
  • Shotcrete
  • Mortar
  • Plaster
  • Glass
  • Rock
  • Concrete roof tiles
  • Sand
  • Soil
  • Stone (granite, limestone, quartzite, shale, slate)
  • Tiles


Silicosis is a lung affliction caused by breathing dust which contains fine particles of crystalline silica. If silica particles are inhaled, they become embedded in the lungs. The lung tissues react by developing fibrotic nodes & scarring around the trapped particles. The scar tissue makes the lungs hard & stiff. Finally, this scaring can greatly reduce the function of the lungs, making it difficult & sometimes painful to breathe.
Silicosis comes in three forms:
Chronic Silicosis: The most common form of disease, it may go undetected for years in the early stages. Chest x-rays may not reveal any signs until 15-20 years post exposure. Once the process of silicosis has commenced the progression can be slowed however, the disease can not be cured.
Accelerated Silicosis: This type of silicosis tends to develop 5-10 years post exposure to high concentrations of crystalline silica dust. Lung x-rays & symptoms are often similar to chronis silicosis, but the onset appears faster & the disease accelerates quickly (hence the name).
Acute Silicosis: Acute silicosis appears rapidly following extreme exposure to high concentrations of crystalline silica. In some cases, silicosis symptoms can become prevalent only weeks after exposure.

Breathing silica dust can also cause lung cancer & increase the chance of developing Tuberculosis.


Although the severity & frequency of symptoms can vary among patients at the time of diagnosis, the most common Silicosis symptoms include:

  1. Chronic dry cough
  2. Shortness of breath
  3. Weight loss
  4. Chest pain
  5. Fever
  6. Dark spots appearing in nails
  7. Low blood oxygen levels
  8. Bluish skin


Many people who have been exposed to crystalline silica think it’s too late to take steps to avoid developing silicosis & other related illnesses, but this is a common misconception.
There are several actions you can take to lower your risk:

  • Perform air monitoring & keep records.
  • Complete regular assessments of risks.
  • Communicate hazards to workers.
  • Use proper work practices & controls to limit exposures.
  • Offer respiratory protection if exposure limits are exceeded.
  • Provide awareness training.
  • Provide medical surveillance to workers exposed to silica.


Like all airborne contaminates, the type of adequate respiratory protection is highly dependent on the amount of contaminate found at the location where duties are carried out. Air sampling, along with a risk assessment should be undertaken prior to commencing the removal of any silica materials.
The major element to increased protection from silica particles is to limit the amount of particles becoming airborne. Many professionals utilise water spraying, vacuuming or ventilation, these measures can reduce dust exposures by up to 80%.
The type of respiratory protection device used for adequate protection is heavily dependent on the removal process & the amount of airborne particles.
It is always recommended that when choosing a suitable respiratory protection device that overprotection is the best protection.


AS/NZS 1715:2009 should play a part in all respiratory programs to ensure the program administrator understands the guidelines required to facilitate a comprehensive respiratory program. AS/NZS 1715:2009 Respiratory Program includes:

  1. Appointment of program administrator.
  2. Selection of Respiratory Protection Equipment (RPE).
  3. Medical screening of users of Respiratory Protection Equipment.
  4. Training.
  5. Issuing of RPE.
  6. Fitting of RPE.
  7. Wearing of RPE.
  8. Maintenance of RPE.
  9. Disposal of equipment.
  10. Record keeping.
  11. Program evaluation.

All requirements for the above program are detailed in AS/NZS 1715:2009.


It’s important to understand the difference between a Fit Check & Fit Test.

Fit Check: Carried out prior to entering a contaminated area & should be part of the wearers donning routine to determine if the respirator is providing an effective seal. This check is carried out every time the respirator is used. A Fit Check follows a successful Fit Test result.

Fit Test: Provides the wearer with a pass or fail result on the respirators ability to seal effectively against the wearers face.
There are two types of Fit Tests – Qualitative & Quantitative.
Qualitative tests are usually simple & fast but may be influenced by the wearer.
Quantitative tests are not subjective or influenced by the wearer, however, involves the purchase of expensive equipment & a fully trained operator.
Records of either tests must be kept for each wearer & stored to form part
of the respiratory program.
A Fit Test should be performed at appropriate intervals:

  1. When there is a change in the wearer’s facial characteristics, e.g weight loss/gain or removal of teeth.
  2. Before the respirator is used by the wearer to ensure the chosen respirator is suitable.
  3. A further fit test should be performed at least once annually


  • It’s found in many construction materials.
  • Silica dust travels deep into your lungs.
  • Long time exposure to small amounts causes harm.
  • Short-time exposure to large amounts causes harm.
  • It causes lung disease, cancer, even death.
  • Airborne particles are too small to see.
  • The effects are worse if you also smoke.

Having the right training and awareness around Silica, and the effects of Silicosis on you, could literally be the difference between life or death. You can download our SILICA TRAINING SHEET here for easy reference.

As a PPE & Workwear solutions provider, contact the team at All Guard Safety to ensure you have the right PPE for the job.

Freephone: 0800 255 482

Source: ProChoice NZ

About the author / Melisa Capper