Crystalline silica: Unsafe by design

June 3, 2025

An excavator and a dumper working on a stone embankment — Image: © Larry Dallaire | iStoc

Dimitra Theodori, Head of the Health and Safety Unit at the European Trade Union Institute, highlights the concept of being unsafe by design when it comes to crystalline silica

As we navigate the ever-evolving world of workplace health and safety, we mustn’t let an age-old danger slip from our focus: crystalline silica dust. While our attention may often be drawn to new risks and future challenges, this ancient hazard still looms large, demanding immediate and decisive action.

A look at crystalline silica

Crystalline silica, a mineral found abundantly in rocks, sand and soil, becomes a deadly threat when these materials are cut or crushed, releasing respirable crystalline silica (RCS) particles into the air. Workers who inhale this dust face serious health risks. RCS is one of the oldest known causes of such devastating diseases as silicosis and lung cancer.

Remarkably, as early as 400 BC, Hippocrates documented respiratory issues in metal workers. Yet, exposure to RCS has only recently been formally acknowledged as a carcinogenic process, with establishing a European Union (EU)-binding occupational exposure limit (OEL) of 0.1 mg/m₃.

This is not a safe limit. No level of RCS exposure is truly ‘safe’, but we’re only fully realising how dangerous the current binding OEL is. A recent report from the Dutch Expert Committee on Occupational Safety and the Nordic Expert Group has revealed alarming new data: exposure at the current OEL can result in almost 10 additional lung cancer deaths per 1,000 workers. ⁽¹⁾ How can we justify accepting this level of risk for workers? It is unimaginable that society would willingly subject individuals to such hazards, particularly when the toll is measured in human lives.

Towards worker safety concerning crystalline silica

On a more positive note, there is encouraging news on the horizon: the binding OEL adopted at the EU level for silica is set to be revised in 2025. The new insights the Dutch and Nordic experts provided are expected to lead to a more protective standard for worker safety. In line with current practices for setting exposure limits for substances where no safe level can be established, the new limit could be as low as 0.00038 mg/m₃ and should not exceed 0.0363 mg/m₃.

However, aiming for a more protective standard alone will not automatically ensure reduced exposure. Without substantial changes to workplace practices, we risk merely adjusting the numbers without truly safeguarding workers’ lives. Although exposure levels have generally decreased over the past 60 years in some industries, we must confront the reality that they may still exceed this threshold.

Approximately 5.5 million workers in the EU are regularly exposed to RCS in a large variety of industries, including mining, farming, construction, foundry processes and the production of glass, artificial stone, ceramics and cement. One critical area that demands our immediate attention is the manufacturing, finishing, and installing of artificial stone countertops, also called engineered stone (ES).

Engineered stone countertops and their impact on workers

In recent decades, ES countertops have surged in popularity, becoming a favoured choice for kitchens and bathrooms due to their aesthetic appeal and durability; their global market value is estimated to be around 25 billion U.S. dollars annually. However, this rising trend brings significant health considerations that cannot be overlooked. The countertops are produced and adjusted to customer specifications through intensive operations such as grinding, cutting, abrasing and polishing.

And because ES countertops contain over 90% finely crushed crystalline silica – significantly more than marble (3%) and granite (30%) – they pose a considerable risk to workers involved in their manufacturing and installation. The dust released during these processes is more reactive and toxic than natural stone dust and contains other potentially toxic components.

With the higher exposure levels of ES causing symptoms to develop earlier, a significant number of young workers in the sector are being diagnosed with accelerated silicosis (currently, one out of four in Australia). This form of the disease is characterised by a latency period of less than 10 years and often progresses rapidly to a stage where no cure exists. Similar cases have also been reported in studies from Spain, Belgium, Israel, China, the U.S. and India. This heightened risk is partly due to the common absence of technical inspections. ES is often processed in small workshops lacking industrial safety standards and installed in residential settings where it isn’t easy to check the exposure.

Moreover, this workforce sector comprises many self-employed individuals or persons engaged in non-traditional work arrangements, such as contract work. These workers frequently lack the legal protections and benefits typically available to traditional employees, including health and safety supervision, health insurance, paid leave, and unemployment benefits.

As a result, they face increased vulnerability and heightened health risks. Studies indicate that even when health surveillance is conducted, early symptoms of the disease are often difficult to detect. Therefore, silicosis is not always detected early.

Is ES as ‘unsafe by design’?

Given the properties of the material and the unique challenges within the ES market, it is difficult to comprehend how such a hazardous product has been permitted to enter the market at all. We could label ES as ‘unsafe by design’ in many ways. It is thus entirely reasonable for Australia to have enacted a ban on its use, supply and manufacture in July of this year. ⁽²⁾ Given the availability of safer alternatives and the significant difficulties associated with controlling exposure in workplaces where ES is processed, this approach is undoubtedly the most sensible strategy. Protecting workers should always be the top priority.