Silica Dust Control in Construction – UK Regulations, Health Risk & Compliance

Silica dust is the leading cause of occupational lung disease in the UK construction sector. The HSE estimates over 500 construction workers die each year from silica-related lung disease — a figure that exceeds fatalities from all other construction causes combined. Despite decades of regulatory attention, silica exposure remains widespread on UK sites because the dust is invisible, the disease develops slowly, and the connection between exposure and diagnosis is often not made until the damage is irreversible.

This guide sets out the health consequences, the legal framework, and the compliance requirements that apply specifically to construction operations — including core drilling, concrete cutting, and grinding — where silica-containing dust is generated at high concentration.

What Is Respirable Crystalline Silica and Why Is It Dangerous?

Crystalline silica is a mineral component of sand, stone, concrete, brick, and mortar. When these materials are cut, drilled, or ground, silica is released as fine airborne particles. The fraction that causes harm is respirable crystalline silica — particles small enough (below approximately 10 microns) to penetrate past the upper airways and lodge in the alveoli, the gas-exchange surfaces deep in the lung.

Once silica particles embed in lung tissue, the immune system attempts to remove them. The attempt fails — silica is insoluble and biologically inert — and the inflammatory response causes progressive fibrosis (scarring). This condition is silicosis. There are three recognised forms:

• Chronic silicosis — develops after 10 or more years of moderate exposure. The most common form. Initially asymptomatic; progressive breathlessness develops over years. Often diagnosed after the worker has left the industry.
• Accelerated silicosis — develops within 5–10 years of higher-intensity exposure. More rapid progression than chronic silicosis.
• Acute silicosis — develops within weeks to months of very high exposure (mass concrete demolition without controls, confined-space blasting). Rapidly fatal. Rare but documented in UK construction.

Silicosis also increases susceptibility to tuberculosis, lung cancer, and autoimmune kidney disease (scleroderma). There is no cure, no treatment that reverses established fibrosis, and no safe level of long-term exposure below which risk is zero.

Which Construction Activities Generate the Highest Silica Exposure?

The HSE's own monitoring data identifies the highest-exposure construction activities as:

• Dry core drilling in concrete and dense masonry — without extraction, exposure can exceed the WEL within minutes. The core barrel concentrates dust at the drill face and the in-and-out movement of the bit creates a continuous emission plume.
• Disc cutting concrete — angle grinder cutting of concrete slabs generates very high airborne concentrations over extended cutting runs. Dry disc cutting without a shroud and extraction is one of the highest single-activity exposure scenarios in UK construction.
• Scabbling and bush-hammering — mechanical surface preparation of concrete generates sustained high-concentration exposure in a localised area.
• Abrasive blasting of masonry — historically the cause of acute silicosis cases; now heavily regulated under the Abrasive Wheels Regulations.
• Breaking out concrete by hand — particularly in confined spaces, where ventilation is inadequate and dust concentrations build rapidly.

For core drilling specifically, the dust extraction guide covers the equipment and setup required to meet the WEL in practice. This article addresses the broader health and compliance framework that applies across all silica-generating construction work.

What Does UK Law Require for Silica Dust Control?

The primary legislation is the Control of Substances Hazardous to Health Regulations 2002 (COSHH). COSHH requires employers to:

1. Assess the risk — identify which tasks generate RCS, estimate likely exposure, and record the assessment. For core drilling and concrete cutting, the HSE's Construction Information Sheet CIS36 provides material-specific guidance and model risk assessments.
2. Prevent or adequately control exposure — using the control hierarchy in order: eliminate (substitute a non-silica-containing material), reduce (wet suppression, vacuum extraction), then — only if engineering controls cannot adequately reduce exposure — supplement with respiratory protective equipment (RPE).
3. Ensure controls are used and maintained — extraction equipment must be maintained in working order. Filters must be replaced at manufacturer-specified intervals. Records of maintenance must be kept.
4. Monitor exposure where necessary — where the risk assessment indicates significant RCS exposure, air monitoring must be carried out to verify that controls are effective. This does not mean continuous monitoring — a representative task-specific measurement programme is sufficient.
5. Provide health surveillance — see below.
6. Provide information, instruction, and training — workers must understand the health risks, the controls in place, and how to use RPE correctly.

On CDM-notifiable projects, the principal contractor is responsible for ensuring all contractors on site comply with COSHH. A CDM construction phase plan must address dust control specifically for silica-generating activities.

What Is Health Surveillance and When Is It Required?

Health surveillance is a COSHH requirement for workers who are regularly exposed to RCS as part of their work. It is not a one-off medical — it is a programme of periodic health checks designed to detect early signs of occupational lung disease while intervention (removing the worker from exposure) can still slow progression.

For silica-exposed construction workers, appropriate health surveillance includes:

• Initial baseline lung function assessment (spirometry) at the start of employment in a silica-exposed role
• Periodic repeat assessments — typically every 1–3 years depending on exposure level
• Records maintained for 40 years after the last entry (COSHH regulation 11)
• Assessment by an occupational health professional or physician with competence in occupational respiratory disease

The COSHH records retention period of 40 years reflects the long latency of silicosis — a worker exposed in their 20s may not develop symptomatic silicosis until their 50s or 60s. The obligation to maintain records therefore extends well beyond normal employment periods.

Health surveillance is not required for occasional or incidental exposure. It is required where a worker's normal duties regularly include tasks that generate significant RCS — which includes any tradesperson who cores concrete or masonry on a regular basis.

What Does HSE Enforcement Look Like in Practice?

The HSE's Construction Division runs targeted inspection programmes focused on high-risk dust activities. Core drilling, disc cutting, and scabbling are priority activities. Inspectors attend sites unannounced and assess:

• Whether a COSHH assessment exists and is task-specific (not a generic form)
• Whether engineering controls (wet suppression or extraction) are in use — a worker drilling dry concrete without a shroud and vacuum is an immediate enforcement concern
• Whether RPE is of the correct specification and correctly fitted (FFP3, not a paper dust mask)
• Whether workers have received training that they can demonstrate
• Whether health surveillance records exist

Enforcement options include verbal advice, improvement notices, prohibition notices (immediate stop on the high-risk activity), and prosecution. HSE prosecutions for silica-related failures have resulted in fines to principal contractors and subcontractors in excess of £100,000 under the Sentencing Council guidelines.

The Control Hierarchy for Construction Silica Dust

COSHH requires controls to be applied in priority order — higher controls must be shown to be impracticable before moving to lower ones:

1. Elimination / Substitution — use a non-silica-containing material, or a method that does not generate airborne dust. In practice, substitution is rarely possible in structural concrete work.
2. Engineering controls — wet suppression — adding water at the cutting face suppresses dust at source. Wet diamond core drilling is the primary engineering control for structural concrete. It does not eliminate all exposure but reduces it significantly. Wet coring slurry must be managed as controlled waste.
3. Engineering controls — local exhaust ventilation (LEV) — dust shroud and Class M vacuum extraction for dry coring. The shroud must be correctly fitted to the drill head and the vacuum must maintain adequate capture velocity at the drill face. See the dust extraction equipment guide for Class M vacuum selection and shroud setup.
4. Respiratory protective equipment (RPE) — FFP3 disposable mask or half-mask with P3 filters as a supplement to engineering controls, not a replacement for them. RPE must be face-fit tested to ensure adequate seal. A paper dust mask (FFP1 or FFP2) does not provide adequate protection for RCS.

Silica Dust and Diamond Core Drilling

Diamond core drilling through concrete and dense masonry generates high-concentration RCS at the drill face. The key control decisions for a core drilling operative are:

• Wet or dry? — structural concrete must be wet cored. Dense block and brick can be dry cored with extraction. The reinforced concrete guide and how-to guide cover the material decision in full.
• Dust shroud fitted? — for dry coring, the shroud must be in place and the vacuum must be switched on before drilling starts. Removing the shroud to check progress exposes the operative to the full dust plume.
• RPE worn? — even with a shroud and Class M vacuum, residual exposure is possible. FFP3 is the correct specification for any core drilling in silica-containing materials.
• Is this a notifiable project? — if so, the COSHH assessment, RPE records, and health surveillance records must all be in order before work starts.

For the full health and safety regulatory framework — COSHH, CDM 2015, GPR scanning, PPE requirements, and HAV controls — see: health and safety in diamond core drilling.