Silica Dust: the hidden danger in construction

Air pollution is a major global health issue, contributing to between 7 and 9 million deaths annually (4.2 million from outdoor air pollution, and 3.8 million from indoor air pollution), including over 700,000 children under five. National Clean Air Day is the UK's largest air pollution campaign - dedicated to highlighting the impact of air pollution on our health and the environment.

With the Construction industry contributing significantly to air pollution (both indoor and outdoor), particularly in urban areas, we have an opportunity to reflect on the volumes and types of air pollution contaminants used in construction, their exposure, controls, and how they are managed throughout the construction process. There is also the potential for using innovative Air Quality and Dust Management Strategies or technologies, and considering how this all fits in with ways to increase both industrial and public awareness, develop understanding and kickstart actions on air pollution and address inequalities.

According to the Centre for Low Emission Construction, while other major sources of air pollution such as transport have rapidly decreased their polluting emissions due to policies like ultra-low emissions zones, construction has increased its overall share in recent decades.

Particles with a diameter of 10 micrometers (PM10 - 10 millionth of a metre) or less can enter deep inside a person’s lungs, while those with a diameter of 2.5 micrometers (PM2.5) or less can penetrate the lung barrier and enter a person’s blood system. The 2019 London Atmospheric Emissions Inventory (LAEI) found that approximately 30% of particulate matter (PM10) emissions come from construction, along with 8% of fine particulate matter (PM2.5).

Construction dust air pollution 

There are several types of harmful dust produced by construction, each posing distinct health risks occupationally and non-occupationally, falling into three main categories:

• Silica Dust (Respirable Crystalline Silica (RCS)): many common construction materials contain silica including plaster, brick, cement, concrete, plasterboard, grout, mortar, natural and engineered stone, sand, asphalt and tile. It is particularly hazardous as it can penetrate deep into the lungs, causing irreversible damage over time and leading to serious respiratory and autoimmune diseases such as silicosis, lung cancer, and chronic obstructive pulmonary disease (COPD).
• Wood Dust: created during the cutting, sanding, and drilling of wood materials (softwoods, hardwoods, and wood-based products like MDF and plywood).  A known carcinogen, causing various cancers as well as asthma, and other respiratory issues. Hardwood dust and formaldehyde are specifically linked to a rare form of nose cancer.
• Non-Silica Dust: materials that contain very little or no silica, such as gypsum, cement, limestone, marble, and dolomite. While generally considered lower in toxicity compared to silica and wood dust, non-silica dust can still pose health risks, especially when mixing cement with sand (which contains silica quartz), as this process poses a risk of exposure to RCS when these materials are cut or ground, releasing airborne dust.

Silica exposure in construction: this generation’s asbestos?

While the dangers of asbestos are now well known, the same could not be said for the awareness of the dangers and impacts of silica dust exposure. This is despite it being recognised as far back as Hippocratic times (c460BC - 370BC), making it potentially the most ancient known air pollutant.

Despite efforts to prevent silica dust exposure and to mitigate its impacts, numerous public health, governmental and industry organisations report it is quickly turning into an emerging global health crisis.

Silica dust is generated through numerous high-risk activities, including cutting, drilling, grinding, and sanding construction materials. When these tasks occur indoors or in confined outdoor spaces, the dust lingers, creating prolonged exposure risks. The microscopic nature of silica particles also makes them easily airborne, traveling beyond the immediate work area and settling on surfaces, where they can be reintroduced into the air through movement or cleaning. 

Policy and industry standards

Regulatory bodies such as Occupational Safety and Health Administration (OSHA), Health and Safety Executive (HSE), and the World Health Organization (WHO) have established strict guidelines to limit silica exposure.

The Environment Act 2021 also contains a raft of provisions which relate to air quality. Local planning authorities often require the air quality impacts of new developments to be assessed as part of the decision-making process, either as a standalone document or as part of a wider Environmental Impact Assessment (EIA).

However, in real terms there is little legislation that explicitly seeks to control RCS dust emissions from construction sites, work practices and activities.

Mitigation strategies

The industry needs a change in the workplace protection paradigm, moving towards a process of continuous improvement rather than just meeting a minimum standard.

The key to reducing silica exposure lies in proactive mitigation:

• Hierarchy of Controls - a step-by-step approach to eliminating or reducing hazards – Workplaces should systematically implement exposure controls in the following order of effectiveness:1. Elimination - 2. Substitution – 3. Engineering Controls – 4. Administrative Controls – 5. Personal Protective Equipment (PPE) including Respiratory Protective Equipment (RPE).
• Wet-cutting methods minimise airborne dust by keeping materials damp during cutting or grinding.
• Dust extraction tools should be used to capture dust at the source, preventing it from dispersing.
• Ventilation through open windows, exhaust systems, or air filtration is essential to prevent accumulation of dust.
• PPE and RPE such as respirators and FP3 masks should always be worn when working with silica-containing materials.

Innovations in next-generation industrial dust management technologies and methodologies are also gaining traction, including air flow technologies to remove dust from equipment surfaces, advanced filtration systems, sensor-enabled dust management systems, and water spray systems, allowing the industry to contribute to reductions in silica dust within the work environment.

However, it is still difficult to both supress and minimise silica dust generation and spread, and more research is needed into innovative monitoring technologies to improve the durability and performance of sensor-based systems capable of generating safety alerts, supporting future regulation.

Call to action

Whether you’re a professional managing construction works or a contractor or a homeowner tackling renovations, prioritising air quality and safe work practices is essential.

As an industry, it’s up to us to advocate for safer practices and push for better air quality in construction zones. Protecting workers, residents, and innocent bystanders from silica dust exposure isn’t just about compliance - it’s about safeguarding health for future generations.

Paul Dockerill Award

As the inaugural winners of the CIOB Paul Dockerill award, Pvotal Consultancy are developing a Residents, Clients & Construction Professionals Silica Excellence (ReACT) toolkit for anyone who is managing, undertaking or involved in housing sector construction works.

We are running a survey to better understand the current state of silica dust awareness, knowledge and experiences as well as identify areas for improvement. The survey takes five minutes to complete, with a chance to win a £50 Amazon voucher: https://www.smartsurvey.co.uk/s/1M6HWA/ 

By sharing your insights and experiences, you will help to contribute to meaningful change and support our efforts to create a healthier, more supportive industry.