What designers need to know about respirable crystalline silica dust

Many natural materials contain a high silica content and need safe processing. The Worktop Fabricators Federation (WFF) has influenced, and helped structure the latest guidance, such as suppressed wet cutting of materials, correct use of PPE and annual health surveillance. This has had an impact on workshop floors, but designers need to be aware of the importance of safety on site.

What is RCS?

Respirable crystalline silica dust (RCS) is both a dust hazard and a carcinogen. Which is why correct processing controls are essential.

Occupationally-acquired silicosis arises when individuals are regularly cutting, grinding or polishing materials which have a high content of crystalline silica, in an environment where proper extraction, suppression and protective equipment are not routinely present, not properly maintained, not routinely worn or not correctly monitored.

Where does it occur?

RCS dust is created only when natural or engineered stone materials are cut, shaped and finished prior to installation.

There is no health risk to showroom staff, installers or consumers associated with specifying, handling, shipping, installing or using engineered stone worktops. Once processed, they are entirely inert and safe; there is no risk of toxicity through touching or food licking the finished product.

Why the current concern?

Medical experts in the UK have identified the first cases of occupationally-acquired silicosis among individuals who have been engaged in stone worktop manufacture. 

The detailed understanding of the causes and exposures in these cases is still in its infancy however it appears to be manifesting most frequently in immigrant young men who appear to have received little or no Health & Safety training from employers, and who have been left to dry-cut worktops out of stone blanks, with no water suppression and minimal dust extraction. (source: British Occupational Hygiene Society)

If there is a common theme around the reported cases, both in the UK and overseas, in occupationally-acquired silicosis, it is that dry-cutting creates a lot of RCS dust. Also, that Personal Protective Equipment alone (assuming it is provided and properly face-fitted, and that the worker wears it correctly) is insufficient to protect workers long-term.  PPE should come last in the hierarchy of risk management, which starts with choice of material, then cascades through suppression and control at point of contact and physical barriers between blade and worker before considering PPE.

What is the cause?

At bottom, it’s customers who want the beauty of a stone worktop but don’t want to pay the price premium associated with proper factory management, controls, health and supplier audits and expensive cutting, polishing and grinding machinery and the associated water and dust-handling infrastructure. 

Stone worktop blanks are internationally available, and land in the UK from a variety of sources, with a variety of provenances (or lack of provenance). Volume discounts notwithstanding, the price of the stone itself is the same to every fabricator. So the only opportunity to cut costs out of the fabrication process is to skimp on the overheads.

 What can I do to reassure my clients?

Only buy from reputable fabricators. Being a WFF member is a great start as they are required to work within WFF guidelines. A professional supplier will be happy to help you with any detailed questions about individual materials, and help you choose alternatives to satisfy a particular specification or performance requirement.

Designers could also advocate for natural stone and other engineered worktop products that might have less silica content.  Processing of all stone worktops should only be carried out by professionals who are properly trained, using appropriate equipment to manage the risks, as dust from cutting has to be contained.

Worktop Fabricators Federation

Launched in 2020, the Worktop Fabricators Federation (WFF) is a non-profit organisation representing businesses using industrial fabrication methods to manufacture large format slabs for surfaces, made from natural stone and similar man-made materials. 

The Federation's objectives and goals are to promote professionalism across the surfaces and stone masonry industries, including the promotion of good working practices and policies for health & safety in the workplace. The WFF is a unified representative voice for the fabricators on matters of industry-wide importance. 

Find out more about the WFF here.

With thanks to Nigel Fletcher and the WFF for the information provided in this article.