HSE’s New Guidance on Working with Engineered Stone (ST3A / Silica Controls)

The UK Health and Safety Executive (HSE) has issued COSHH guidance (ST3A) specifically for engineered stone fabrication. It clarifies legal requirements under COSHH to control respirable crystalline silica (RCS) dust, which causes silicosis (an incurable, potentially fatal lung disease).

Dry cutting of engineered stone is now declared unacceptable. Water suppression (e.g., on-tool water) is the required standard to meet legal duties. This is not a new law or outright ban but a clear statement of what “adequate control” means in practice.

Main Requirements for Employers (Fabricators)

Switch to low-silica engineered stone where possible (viable alternatives exist at similar quality).
Use wet methods (on-tool water suppression) and control mist — dry cutting must stop unless an equally or more effective control can be demonstrated.
Provide suitable respiratory protective equipment (RPE).
Implement health surveillance for exposed workers (questionnaires, lung function tests, chest X-rays as advised).
Follow the hierarchy of controls — focus on prevention at source rather than relying on PPE alone.

Enforcement

Over 1,000 targeted inspections of fabricators across Great Britain over the next 12 months (already underway as of May 2026).
Enforcement action (improvement/prohibition notices, etc.) for non-compliance.
Aimed at creating a level playing field — those following good practice are not undercut by those cutting corners.

Health Matters

Recent silicosis cases in young workers (sometimes developing in months/years rather than decades) from high-silica engineered stone (up to 95% crystalline silica) prompted this action. Research showed dry methods produce 5–10 times higher RCS exposure than wet methods.

Impact on Builders, Installers & Refurbishment Work

The new ST3A guidance is targeted at fabrication shops, but for our busy builders, installers, and refurbishment contractors, ensure you managing working with engineered stone on site.

Where possible, use prefabricated / pre-cut worktops to minimise on-site processing.
On-site cutting, trimming, or modification of engineered stone worktops, slabs, or panels must follow the same controls (wet methods preferred; dry cutting generally unacceptable).
General construction silica rules continue to apply (HSE guidance on RCS in construction): water suppression, dust extraction (e.g.,dust shrouds + HEPA vacuums), RPE, and good housekeeping for tasks like cutting tiles, bricks, concrete, or stone.
Refurbishment of occupied premises requires extra care to protect occupants from dust migration.
Employers must still assess RCS risks, provide health surveillance where appropriate, and ensure workers are trained/competent.

Silica remains a major killer in construction linked to >500 deaths/year per HSE estimates, so expect continued focus during site inspections, (and rightly so!)

Resources:

Full guidance: Search HSE for ST3A or visit hse.gov.uk/stonemasonry (COSHH Essentials sheet).
General silica advice: INDG463 and other COSHH sheets.

Let’s keep health & safety simple and effective💼🛡️If you are concerned about your arrangements, please do reach out at hello@shedoessafety.co.uk

Laura Tull, CertIOSH, AIFSM

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