Fibre Reinforced Facade Encyclopedia: Composition
Silica free describes a material formulated without crystalline silica, the mineral whose respirable dust causes silicosis. The term matters because Australia became the first country in the world to prohibit engineered stone, with the ban on manufacture, supply, processing and installation taking effect on 1 July 2024. A silica free composite is one where the filler and reinforcement carry no crystalline silica, so cutting, grinding and polishing it cannot generate respirable crystalline silica in the first place.
The workplace exposure standard for respirable crystalline silica in Australia is 0.05 mg per cubic metre averaged over eight hours. Dry cutting an engineered stone slab can exceed that figure by two orders of magnitude within minutes.
At a glance
| Property | Typical value | Note |
|---|---|---|
| Prohibition commenced | 1 July 2024 | Manufacture, supply, processing and installation of engineered stone |
| Crystalline silica in engineered stone | Commonly 70 to 95% by weight | Lower in some marble look and terrazzo look products |
| Workplace exposure standard | 0.05 mg/m³, eight hour time weighted average | Respirable crystalline silica, in force since 1 July 2020 |
| Wider silica duties | From 1 September 2024 | Silica risk control plan for high risk crystalline silica work |
| Excluded from the ban | Concrete, brick, tile, grout, render and resin free porcelain | Excluded from the prohibition, not from the silica duties |
| Low silica engineered stone | Still prohibited | Ministers declined to set a low silica threshold |
| Test method for silica content | X-ray diffraction, for example NIOSH 7500 | Ask for the analysis, not the marketing claim |
| Silica content of a ShapeShell benchtop panel |
Why crystalline silica is regulated
Crystalline silica is quartz, cristobalite and tridymite. It is harmless as a solid; the hazard is the respirable fraction, particles small enough to reach the deep lung, released whenever a silica bearing material is cut, ground or polished dry. Prolonged exposure causes silicosis, an irreversible scarring of lung tissue, and is associated with lung cancer and chronic obstructive pulmonary disease.
Engineered stone concentrated the risk because the product is typically 70 to 95 percent crystalline silica by weight, far higher than natural granite, and because fabrication happens in small workshops where dust control was often poor. Australian occupational physicians began seeing accelerated silicosis in stonemasons in their thirties, which is what drove the regulatory response.
What the Australian ban actually covers
Work health and safety ministers agreed in December 2023 to prohibit engineered stone, and the prohibition took effect under the model Work Health and Safety Regulations on 1 July 2024 in most jurisdictions, with limited transitional arrangements for contracts already on foot. It bans the manufacture, supply, processing and installation of engineered stone benchtops, panels and slabs.
Two points are routinely misread. First, the prohibition is on the product category, and ministers declined to allow a low silica version, so slabs marketed as low silica engineered stone are caught by it. Second, the regulations exclude a list of other products from the prohibition: concrete and cement products, bricks, pavers and similar blocks, ceramic tiles, grout, mortar and render, plasterboard, roof tiles, and porcelain or sintered products that do not contain resin. Those exclusions are from the ban, not from the general duty to control silica dust.
What silica free means, and what it does not
There is no legal definition of silica free and no certification mark behind the phrase. It is a compositional claim, and it should be verified the way any other compositional claim is verified: a safety data sheet listing every constituent, a statement of the filler and reinforcement chemistry, and, where the stakes justify it, an X-ray diffraction analysis of the cured product reported against a stated detection limit.
A genuinely silica free composite uses fillers such as aluminium trihydrate, calcium carbonate or alumina rather than quartz flour or silica sand, and glass fibre rather than a mineral filler carrying quartz. Glass fibre itself is amorphous, not crystalline, so it does not contribute to the respirable crystalline silica fraction. Silica free says nothing at all about fire performance, strength, stain resistance or durability; those remain separate questions with separate evidence.
Where this leaves cementitious panels
Glass fibre reinforced concrete contains fine silica sand, and fibre cement contains ground quartz, so both generate respirable crystalline silica when cut or ground on site. Neither is prohibited, and neither should be. What they require is the ordinary control hierarchy: factory cutting wherever possible, wet cutting or on-tool extraction, exclusion of bystanders, respiratory protection selected for the task, air monitoring and health monitoring where the work is high risk.
This is a practical argument for factory finished panels over site cut sheet: every cut moved into a workshop with extraction is exposure removed from an uncontrolled site. Where a project needs a silica free material at the point of fabrication, a polymer composite with non-silica fillers is the route that exists.
Specifying it
- Name the requirement as an absence of crystalline silica in the cured product, not as a trade description
- Require the safety data sheet and a constituent declaration from the manufacturer
- Require an X-ray diffraction result with a stated limit of detection where the claim is load bearing
- Keep the fire, structural and durability requirements separate and evidenced on their own terms
- Specify the fabrication method, since any silica bearing material cut on site is still a dust problem
For a benchtop or wet area panel, add the performance requirements that engineered stone was chosen for in the first place: stain and chemical resistance, thermal shock at a cooktop, impact resistance at an edge, and the repairability of the surface.
Standards and references
- Model Work Health and Safety Regulations, prohibition on engineered stone (from 1 July 2024) and crystalline silica substance duties (from 1 September 2024)
- Safe Work Australia Workplace Exposure Standards for Airborne Contaminants: respirable crystalline silica 0.05 mg/m³ eight hour TWA
- Safe Work Australia Code of Practice: Managing the risks of respirable crystalline silica from engineered stone in the workplace
- AS 2985 Workplace atmospheres: method for sampling and gravimetric determination of respirable dust
- NIOSH Method 7500 Silica, crystalline, by X-ray diffraction
- AS 3640 Workplace atmospheres: method for sampling inspirable dust
Related terms
Questions specifiers ask
Is engineered stone banned in Australia?
Yes. The manufacture, supply, processing and installation of engineered stone has been prohibited since 1 July 2024, with limited transitional arrangements for contracts entered into beforehand. Removal, repair and disposal of stone already installed is allowed under controlled conditions.
Are low silica engineered stone products allowed?
No. Ministers considered and rejected a low silica threshold, so products marketed as low silica engineered stone remain within the prohibition. Check the regulation as adopted in your jurisdiction for the current wording.
Is concrete or GRC affected by the ban?
They are excluded from the engineered stone prohibition. They are not excluded from the crystalline silica duties, because cutting or grinding them releases respirable crystalline silica and those controls still apply.
How do I verify a silica free claim?
Ask for the safety data sheet and a constituent declaration, and for X-ray diffraction analysis of the cured product with a stated limit of detection. Silica free is a marketing phrase until it is backed by composition data.
Does silica free mean the material is safer in every respect?
No. It removes one specific hazard, respirable crystalline silica. Dust from any cutting operation still needs control, and fire, structural and durability performance are separate questions that need their own evidence.
Looking at a silica free benchtop or wet area panel and need the composition and performance data in writing? Talk to us about the standard product range. Contact ShapeShift Technologies
Reviewed by Richard Halvorsen, General Manager, ShapeShift Technologies. Last updated September 2026.