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Silica Dust

Silica dust can cause serious health problems and even death to those who work on construction sites

Silica dust (also known as respirable crystalline silica or RCS) can seriously damage workers' health and regularly breathing in this type of hazardous substance over a long period of time can cause life-changing lung diseases.

Silica is a substance naturally found in certain types of stone, rock, sand, and clay. Working with these materials can create a very fine dust that can be easily inhaled. Once inside the lungs, it causes swelling (inflammation) and gradually leads to areas of hardened and scarred lung tissue (fibrosis)1.

Silica dust, along with wood dust, is one of the main types of construction dusts. It is present in sand, sandstone, granite and commonly found in many other construction materials such as concrete and mortar2.

Silica Dust Health Risks

The Building Safety Group have recently stated that breaches in dust control are the biggest health hazard on construction sites3.

Silica dust is generated from a range of materials during many common construction tasks including cutting, drilling, grinding, and polishing. Some of the dust in fine enough to get deep into workers' lungs. The fine dust is known as respirable crystalline silica (RCS) and is too fine to see with normal lighting4.

% of Silica Content in Common Building Materials

Substance % of Silica Content
Brick Up to 30
Concrete, cement, mortar 25 to 70
Tile 30-45
Sandstone, gritstone, quartzite More than 70
Granite Up to 30
Sand, gravel, flint More than 70
Slate Up to 40
Flint More than 80

The amounts needed to cause this damage are not large. The amount of silica dust that would result in a person exposed to the legal unit is shown next to the penny. The law requires companies to make sure workers are breathing in levels of silica dust well below the illustrated amount5.

Silica Dust

Protecting Workers from Silica Dust

The APPG has engaged with leading organisations and industry experts to launch a new report on Respiratory Protection and the risks of Silica Dust. After citing our evidence in their 2020 report - Silica - The Next Asbestos", further investigation has been carried out to identify risk reduction strategies to decrease exposure to ill health, reducing the burden on healthcare services and help save lives. The 2023 APPG Report "Improving Silicosis Outcomes in the UK" has once again cited our recommendations of the most effective way to reduce exposure of Respirable Crystalline Silica by following the hierarchy of control. To view the full 2023 APPG report, you can download it here.

From October 2022, the HSE started inspecting manufacturing businesses across England, Wales and Scotland as part of an initiative to protect workers using materials such as stone, rocks, sand and clay. Focusing on the respiratory risks and fatal lung diseases respirable crystalline silica (RCS) can cause, inspectors are visiting manufacturing business where the natural substance can be found. We've compiled advice on how to ensure that you are protecting your workers from RCS and advise on what to expect from a HSE visit. To download our advice sheet, click here.

Respiratory Risks

Silica dust is the biggest respiratory risk to construction workers after asbestos. The HSE estimates that every year 500 construction workers die from exposure to silica dust and around 13,000 deaths are a result of occupational lung disease and cancer5.

Employees with heavy or prolonged exposure to RCS are at risk of developing lung cancer and other respiratory diseases. While some symptoms appear quickly, most happen over several years after regularly breathing in small amounts of dust which build up and damage the airways.


Silicosis can cause severe breathing problems and increases the risk of lung infections. Silicosis usually follows exposure to RCS over many years, but extremely high exposures can cause acute silicosis more quickly. Occupations most exposed to RCS include quarrying, slate works, foundries, potteries, stonemasonry, construction and industries using silica flour.

Symptoms of Silicosis include breathing difficulties and a chronic cough which may not appear before retirement. Silicosis can be extremely disabling and lead to early death.


The term "pneumoconiosis" refers to a group of lung diseases caused by the inhalation - and retention in the lungs - of dusts. The most commonly occurring types of pneumoconiosis (apart from asbestosis) are coal worker's pneumoconiosis, arising from the inhalation of coal dust, and silicosis, arising from the inhalation of respirable crystalline silica (RCS). There is a long delay - up to ten years or more - between exposure and onset of disease, so most new cases or deaths from pneumoconiosis reflect the working conditions of the past and occur in individuals who have retired.

Pneumoconiosis cases can be classified in four groups:

  • coal worker's pneumoconiosis
  • asbestosis
  • silicosis
  • other unspecified pneumoconiosis

The industries affected by silicosis and other pneumoconiosis cases are quarrying, foundries and potteries, suggesting that silica is the predominant cause.

Chronic Obstructive Pulmonary Disease (COPD)

COPD is a group of lung diseases including bronchitis and emphysema. It results in severe breathlessness, prolonged coughing and chronic disability. It is estimated that 4000 COPD deaths a year are a result from past exposure to hazardous substances in the workplace, with construction workers being a significant at-risk group4.

Eye and Skin Contact with Dust

Dust particles produced during the cutting, grinding, and drilling of materials can cause eye damage or irritation. When dust enters the eyes, it can react with the natural moisture leading to redness, burns, or in serious cases, blindness. Dust can land and become trapped between loose clothing and skin. The dust may then react with sweat or damp clothing to form a corrosive solution, which can damage skin6.

Controlling Silica Dust

Silica and Control of Substances Hazardous to Health Regulations (COSHH)

COSHH, sets out the legal requirements to protect workers from health risks caused from hazardous substances, including construction dust, at work. Employers have a duty to carry out a suitable and sufficient risk assessment and take steps to ensure they prevent or adequately control exposure. A specialist advisor, such as an occupational hygienist may be required to provide guidance on the level of risk posed by dusts and the appropriate control measures for specific circumstances.

COSHH states that, where it is not reasonably practicable to prevent exposure to a hazardous substance, control of that exposure should only be treated as adequate if:

  • The principles of good practice for the control of exposure are applied
  • Any workplace exposure limit (WEL) is not exceeded
  • For a substance that has the potential to cause cancer or occupational asthma exposure is reduced to as low a level as is reasonably practicable

Hierarchy of Control

Elimination and Substitution

Reduce the dust - before any dusty activities begin, the type of construction dust which may be generated should be considered. Working methods, building materials used and procedures for preventing airborne dust arising in the first place should be top priority.

Engineering Controls: Reducing the Amount of Exposure

If airborne dust cannot be avoided, then working methods for minimising the amount of airborne dust generated and breathed in must be followed.

Water - water needs to be used correctly to suppress dust clouds. There should be a constant supply for the full duration of work.

Vacuum Extraction - a type of local exhaust ventilation (LEV) that fits directly onto tools and a common way for business to control dusts. All LEV systems work in the same way by capturing and extracting contaminated air either by hand or machine at source, before dusts can be breathed in, and transporting them safely away to an emission point and to a filter / scrubber.

LEV protects everyone in the workplace, whilst respiratory protection equipment (RPE) only protects the person wearing it.

Introducing LEV

Buying the right LEV equipment is a critical step. Many employers buy LEV equipment to find that it doesn't work. That's because the wrong type has been purchased or because it hasn't been installed or maintained properly.

To help you avoid expensive mistakes and to ensure you are controlling exposures effectively; we can offer site surveys, advice on product specification and selection, training and on-going service and maintenance.

Introducing LEV

Respiratory Protective Equipment (RPE)

The laws governing the control of hazardous substances in the workplace state that you should only use RPE after you have taken all other reasonably practicable measures to prevent or control exposure. By going through the risk assessment, you can determine whether the use of RPE is necessary in your workplace.

Dust monitoring will help determine whether hazardous dust has been adequately removed through other means such as extraction. If the exposure is reduced, but a percentage is still present, then appropriate RPE will need to be introduced.

Remember, RPE must only be used as a last resort where there are risks to health and safety that cannot be controlled by other means. When supplying RPE, it is the duty of the employer to select the correct RPE, ensure it is suitable for the task, provide training on the equipment and ensure the equipment is stored, cleaned and maintained correctly. Regular inspection is also a requirement to make sure it is fit for purpose.

Respiratory Protective Equipment (RPE)

Disposable Masks

As a minimum, workers in construction should be using RPE with an FFP3 particulate filter. Disposable masks are available with different protection factors and it is recommended that a protection factor of at least 20 is specified. All users must be clean shaven when wearing tight-fitting respirators and require a face fit test.

Reusable Masks

Reusable masks allow the air to pass into the mask through either a filter or draws air from another source through the inhalation valve and available as either a half-face or full-face mask. When working with construction dust, such as silica, ensure the right particulate filter (P3) has been selected. All users must be clean shaven when wearing tight-fitting respirators and require a face fit test.

Powered Air Purifying Respirators (PAPR)

Powered air systems provide extensive protection from hazardous dusts such as silica and create an air flow inside either a tight fitting facepiece or loose-fitting hood. PAPRs worn with loose-fitting masks can be worn by those with facial hair and a face fit test is not required.

Respiratory Management Programme

RPE is widely selected as a protection measure after the hierarchy of controls have been followed and the hazard remains. Unfortunately, up to 50% of respirators fail to offer the assumed protection level, therefore it is essential that an effective respiratory management programme is implemented to help protect people at work.

There are six key elements to implementing an effective respiratory management programme:

Correct Product Selection
Correct Product Selection

Employers should ensure their employees are issued with adequate RPE to control the hazards relating to their tasks and unique working environment. We can support you in selecting the right products for your needs.

RPE Training
RPE Training

Not only should employees be issued with correct RPE but they should be correctly trained in wearing and using it. We can help advise you on the training your employees require, whether that's a tailor-made learning package or one of our standard courses.

Face Fit Testing by Competent Fit2Fit Approved Specialists
Face Fit Testing by Competent Fit2Fit Approved Specialists

Wearers of tight-fitting or close-fitting RPE must receive a face fit test for each variety of mask they wear, to ensure it fits correctly and achieves the tight seal required to provide protection. Ideally, this should be carried out at the mask selection stage and repeated every two years or sooner depending on the risks, if the wearers facial features change or if switching to a new mask manufacturer or model.

Our team of Fit2Fit technicians can carry out Face Fit Testing throughout the UK and also deliver Fit2Fit approved training courses on qualitative face fit testing.

Ongoing Equipment Maintenance and Inspections
Ongoing Equipment Maintenance and Inspections

Poorly maintained respiratory equipment may not offer the assumed level of protection to the wearer, so workers need to be trained how to correctly use and wear it, how to clean and maintain it to industry standards, and when it should be replaced. We can train you to conduct your own monthly COSHH inspections or undertake them for you as part of our managed services package. We carry out required manufacturers servicing to ensure your equipment is maintained correctly to provide adequate protection.

Record Keeping of RPE
Record Keeping of RPE

You should ensure valid records are available for inspection if required. Our managed services offer gives you peace of mind that your employee training requirements are managed and your equipment inspections are scheduled and compliance records are fully up to date with legislation.

Storing Your RPE
Storing Your RPE

When storing your RPE ensure it is kept clean, can be easily accessed and is not exposed to potentially damaging conditions. Store your RPE in a dry place and avoid storing with other items such as consumables or machinery.