Engineered stone and silica: what to ask

At a glance

All HSE items were read on 5 November 2026. HSE's pages change: check the current wording before you rely on this sheet.

What HSE has published, and when

The Health and Safety Executive (HSE) regulates work health and safety in Great Britain. In spring 2026 it published its first guidance sheet specifically for engineered stone and started a programme of inspections of fabricators. The dates below are those shown on each page or release.

HSE has not, in what we found on 5 November 2026, published a later press release on engineered stone. The exposure limit for respirable crystalline silica is in HSE's EH40/2005 list (4th edition 2020, Table 1): 0.1 mg/m³ as an 8-hour time-weighted average. HSE's EH40 page, updated 26 February 2026, says revised limits will be introduced for three outstanding EU limits without naming them, so check the current list.

What HSE asks of fabricators, and what it leaves out

HSE's sheet ST3A is written for managers of fabrication and installation work. Under the Control of Substances Hazardous to Health Regulations 2002 (COSHH), employers must prevent exposure or, where that is not reasonably practicable, adequately control it. For cutting and polishing engineered stone with powered hand-held rotary tools, the sheet asks for:

• work with stone that has the lowest crystalline silica content;
• on-tool water suppression, with the mist controlled, because the mist contains crystalline silica; partly enclosed, externally vented local exhaust ventilation is described for mist;
• powered air purifying respirators with an assigned protection factor (APF) of at least 20 when processing, cleaning or maintaining machinery;
• health surveillance for workers who are regularly exposed, where chronic obstructive pulmonary disease or silicosis may reasonably develop;
• regular review of the controls, and daily cleaning of equipment and the work area by wet methods or a Class M vacuum, with no dry brushing or compressed air.

HSE's page for installing stone worktops adds that cutting, shaping and polishing should be done in a suitably equipped workplace, that sink and tap holes should be cut off site, that worktops should be cleaned before transport, and that any unavoidable site cut should be made in a well-ventilated, restricted area, ideally outdoors, with a water supply.

What HSE's material does not say. It does not define ‘low’ or ‘high’ silica content: sheet ST3A says only ‘the lowest crystalline silica content’. It does not address specifiers or designers, who appear nowhere in the sheet or the two press releases; the releases name fabricators, installers and distributors, and manufacturers, suppliers and importers. Sheet ST3A covers hand-held rotary tools; other tasks have other sheets. And the pages we read concern the dust made while stone is cut, ground or polished: they do not address finished, installed surfaces, and this sheet makes no statement about them.

Which worktop materials carry silica

HSE gives one figure for a material: engineered stone can contain up to 95% crystalline silica. For natural stone it gives none. The only published ranges we could read are from SafeWork NSW, an Australian regulator. They are indicative, not UK guidance, and natural stone varies by quarry.

Natural quartzite is not engineered stone, but that does not make it low in silica. It is a natural rock, quarried in slabs, with no resin; our guide to quartzite explains what it is. It is composed mainly of quartz, which is crystalline silica, so the dust made by cutting it is respirable crystalline silica dust and the same COSHH duty applies. HSE's engineered stone sheet is written for resin-bound stone; its pages on silica dust and on installing stone worktops cover natural and artificial stone alike. Do not specify quartzite as a low-silica alternative.

Eight questions to put to a fabricator

These questions help a specifier do reasonable due diligence. They do not move any legal duty from the fabricator to you. Ask for the answers in writing, and ask the workshop that will do the work, not only the supplier of the slab. The numbers match the balloons in the drawing.

1. How will my material be cut, edged, drilled and polished? HSE's sheet describes on-tool water suppression with the mist controlled, and rules out dry cutting unless an equally or more effective control can be shown. Ask for the method for every process, including polishing and cut-outs.
2. What is the crystalline silica content of this material, and can I see the safety data sheet? Ask for the percentage by weight for each material offered, and whether a lower-silica product meets the brief. HSE does not say what ‘low’ means, so the number is the useful answer.
3. What respiratory protection do your workers wear? Sheet ST3A asks for powered air purifying respirators with an assigned protection factor of at least 20 for processing, cleaning and maintaining machinery.
4. Is there a health surveillance programme for workers who are regularly exposed, and who runs it? The sheet asks for one where chronic obstructive pulmonary disease or silicosis may reasonably develop, run with advice from a competent occupational health professional. Do not ask for individual workers' health information.
5. What dust and mist extraction and cleaning do you use? Sheet ST3A describes extraction for mist, wet cleaning or Class M vacuums, and no dry brushing or compressed air. Worktops should also be cleaned before they leave the workshop.
6. Has HSE served an enforcement notice on you, or on the workshop that will do the work? HSE publishes enforcement notices in a public register at resources.hse.gov.uk/notices, which you can check yourself.
7. What is cut off site, and what is cut on site? HSE's installer page asks for sink and tap holes to be cut off site and for any unavoidable site cut to be made in a well-ventilated, restricted area, ideally outdoors, with water supplied.
8. Who installs, and how are waste and slurry handled? Installers should be trained in the silica risk and clean up by wet methods or a Class M vacuum, never with compressed air.

The Worktop Fabricators Federation, a trade body, says on its silica page that its members keep data sheets showing where their materials come from, and suggests asking about dust controls, health audits of workers and lower-silica alternatives. A membership or quality mark tells you what the body asks of its members. It does not replace your own questions.

Specifying lower-risk options, and what we cannot say

HSE's May 2026 release says lower-silica engineered stone is available at the same quality, and that HSE is working with manufacturers, suppliers and importers to encourage its supply. Whether a lower-silica product suits your brief is a question for the supplier, and the silica content and safety data sheet are the evidence.

There are other surface materials, among them natural marble and limestone, sintered stone, large-format porcelain and solid surface. Each has its own fabrication hazards, its own performance and its own limits: marble etches, for example (see natural stone finishes), and large-format slabs need fabricators experienced with them. None is a safe alternative, and dust of any kind needs assessing and controlling. Choose the material for what it has to do, then ask the questions above of whichever you choose.

A workable order is: decide the material for performance and appearance; ask for the silica declaration and safety data sheet; write the fabrication method and the confirmations into the specification; ask for the fabricator's written answers at tender; and check the arrangements again before work starts. Whether and how health and safety law bears on a designer's choice of material is a matter for your own adviser: HSE's 2026 materials do not address it.

We recommend putting these questions to the partner stone workshop for any stone commission, and the answers should be in writing. Until we hold them, this sheet makes no statement about how our partner works.

All cutting, grinding, edging, drilling and polishing of [engineered stone / natural stone] to use on-tool water suppression with mist control. Dry cutting is not permitted [unless the fabricator shows in writing, before work starts, an equally or more effective control]. Sink, hob and tap cut-outs to be made in the workshop before delivery.

The supplier is to declare the crystalline silica content ([ ]% by weight) of each material offered and issue the current safety data sheet with the tender. Where [engineered stone] is specified, the tender is to name the lowest-silica product that meets [colour and performance requirement] and any lower-silica alternative offered.

Before order the fabricator is to confirm in writing: that a COSHH assessment has been made for the work; the respiratory protective equipment provided [powered air purifying respirators, assigned protection factor at least 20, for hand-held rotary tools]; the health surveillance arrangements; the dust and mist extraction in use; and any HSE enforcement notice in the last [12] months.

No dry cutting, dry sweeping or compressed-air cleaning on site. Any unavoidable site cut to be made [outdoors / in a restricted, ventilated area] with a water supply, by trained operatives. Clean by wet methods or a Class M vacuum, and remove waste and slurry [daily].

Standards and sources

• HSE, Working engineered stone: control silica risk: updated 29 April 2026; read 5 Nov 2026.
• HSE, COSHH essentials sheet ST3A: PDF dated 23 April 2026; read in full 5 Nov 2026.
• HSE press releases, 11 May 2026 and 25 June 2026: read 5 Nov 2026.
• HSE, Silica dust and Installing stone worktops: updated 29 April 2026 and 16 January 2025; read 5 Nov 2026.
• HSE, EH40/2005 Workplace exposure limits, 4th edition 2020: Table 1; page updated 26 Feb 2026; read 5 Nov 2026.
• SafeWork NSW (Australia), What are crystalline silica and engineered stone: indicative ranges, not UK; undated; read 5 Nov 2026.
• Worktop Fabricators Federation, Silica and silicosis: trade body page; undated; read 5 Nov 2026.

Questions we are asked

Is engineered stone banned in the UK?

HSE's May 2026 guidance is not a ban. HSE calls it guidance, not new law or a formal prohibition, while describing the controls in it, such as water suppression, suitable respiratory protection and health surveillance, as legal requirements under COSHH. It has also served prohibition notices on fabricators who failed inspections. Check HSE's site for anything newer.

Is natural quartzite the same as engineered quartz?

No. Natural quartzite is a rock, quarried in slabs, with no resin binder; engineered stone is crushed stone or minerals bonded with resin. But quartzite is composed mainly of quartz, which is crystalline silica, so cutting it makes respirable crystalline silica dust and the same COSHH duty applies. Do not treat it as a low-silica option.

Can I still specify engineered stone?

HSE's guidance is directed at fabricators and installers, who must control the dust, and it asks them to use stone with the lowest crystalline silica content. It does not address specifiers. If you specify engineered stone, ask for the silica content and safety data sheet, ask whether a lower-silica product meets the brief, and put the fabrication method in the specification. Take advice from your own adviser on what applies to you.

What is dry cutting, and why does HSE rule it out?

Dry cutting means cutting, grinding or polishing stone without water on the tool. HSE's research found that dry fabrication typically gives exposure to respirable crystalline silica five to ten times higher than wet methods using the same tools, so it has said the guidance effectively rules it out unless a business can show an equally effective or better control.

What does low-silica mean?

HSE's sheet asks for stone with the lowest crystalline silica content and does not define low or high. Ask the supplier for the silica content as a percentage by weight, in writing, with the safety data sheet, and compare it across the products offered.

Does this page say whether a finished worktop is safe?

No. The HSE pages we read are about the dust made when stone is cut, ground or polished, and about controlling it in the workshop and on site. They do not address finished, installed surfaces, and this sheet makes no statement about them.