Considered by many a malady of the past, silicosis, a progressive and incurable lung disease, has emerged on a worrying scale amongst workers fabricating and installing artificial stone kitchen and bathroom countertops. Silicosis is caused by the long-term inhalation of fine dust particles known as respirable crystalline silica. Silicosis’s reappearance in developed economies such as Europe, Australia and the United States, with young workers once again dying of this entirely preventable disease, begs the question: where did it all go wrong?

Bob, a 41-year-old manual worker, was referred to our clinic for occupational diseases in the University Hospital of Leuven (Belgium) by his lung specialist. He complained of a dry cough, but his lung function tests did not show any abnormalities. However, when we saw the image of his chest CT scan, we were struck by the numerous small white spots all over his lungs, typical of silicosis. How was it possible that this man had been struck by this disease at such a young age, and where did the silica dust that had caused it come from?

Bob had been working for 10 years in a two-man company producing and installing artificial stone kitchen countertops, a job not usually linked with the risk of silicosis. However, he told us that he made the countertops by mixing epoxy resin, gravel, sand, pigment, and fine silica flour. After the countertops were cured, he had to grind and polish them, probably leading to a high degree of silica exposure, as there was no appropriate dust control at the workshop. His yearly occupational health examination did not include a chest X-ray, so he had never known that something was going on in his lungs. We then discovered that Bob’s only colleague also had breathing problems. When we invited him for a consultation, he told us he had been taking asthma medication for the last three years but that it had not helped his symptoms. When we saw his CT scan, the resemblance with that of his co-worker was striking: there was no doubt that he also had silicosis.

Silicosis: a very contemporary problem

Silicosis, an occupational disease first recognised centuries ago, remains a global health problem today, mainly hitting low- and middle-income countries. In the United States, Australia and Europe, the occurrence of silicosis has been declining in recent decades due to improved prevention strategies but also to a large extent because many hazardous industries such as mining have closed down or moved to the global South. This made many in Europe think that silicosis was a disease of the past. However, it has never fully disappeared. It is estimated that in the EU, five million workers are potentially regularly exposed to respirable crystalline silica. Those working in quarrying, mining, stonemasonry, construction, roadworks, sandblasting, ceramics and foundries are most at risk.

Silicosis regularly re-emerges in new production processes or industries. One of the worst recent outbreaks occurred in Turkey amongst workers sandblasting denim jeans to give them a "worn-out" look. Sandblasting was done mostly by young men in unregistered workplaces without any protection, leading to high exposure to fine silica dust and extremely high rates of silicosis – and, in many cases, death. These findings led to a Turkish ban on the process in 2009, after which much of the production – and the accompanying working conditions – moved to countries such as China, Bangladesh, India and Pakistan.

The emergence of silicosis in the artificial stone countertop industry in the last decade has been reported in countries as diverse as Spain, Australia, Israel, Italy, the United States, Belgium, New Zealand and China. The market for these countertops has been booming since 2000. Many customers prefer these stones as they are available in many different colours and patterns and are indistinguishable from natural stone, but cheaper. Artificial stone is formed by mixing a "filler" with a synthetic resin, which is then moulded into slabs and heat-cured. In most stones, the filler is a crushed rock containing high percentages of crystalline silica (quartz or cristobalite). As a result, the silica content of artificial stone is generally more than 90%, far higher than most natural stones such as marble (3%) or granite (30%, on average). The manufacturers then sell the stones to countertop fabrication shops (generally very small companies) who cut the stones into the right size to fit in customers’ kitchens or bathrooms.

Company negligence in Spain

In Spain, Cosentino is the largest producer of these countertops, a business giant with a turnover of close to 1 000 million euros. In 2009, the Spanish trade union Comisiones Obreras (CCOO) was the first to alert the media that one of its members, a 29-year-old stonemason, had been diagnosed with silicosis after barely five years of working with artificial stones. He had been employed in one of the small workshops or "marmolerías", where workers cut, drill, grind and polish Cosentino’s stones before installing them in customers’ homes.

In a "marmolería" working with Cosentino stones in the port city of Huelva, nine workers were diagnosed with silicosis between 2009 and 2010. Two of them died because of the severity of their disease. In 2019, two of the company’s managers, a prevention technician and a doctor from the occupational health service FREMAP, each received a sentence of one year and three months in jail for two homicides and seven injuries due to negligence. The judge concluded that the occupational doctor assigned to the company by FREMAP did not apply the obligatory health surveillance protocols.

Cosentino has always denied all responsibility in how the material was handled in the small workshops to which their product was supplied. However, a judgment of the Criminal Court of Bilbao, confirmed by the Provincial Court of Biscay in 2017, determined that as the manufacturer of the artificial stones the company was jointly responsible for causing the disease in several of these workers in smaller workshops because it did not inform them about any risk derived from handling their product. Moreover, workers at the Cosentino plant itself also developed silicosis, with cases appearing as recently as late 2019. According to the CCOO more than 700 artificial stone workers have been struck by the disease.

The Australian workers diagnosed young

Australia does not have any artificial stone manufacturing industry; all stones are imported. Nevertheless, it too is experiencing a major silicosis outbreak. In 2018, the news programme 7.30 brought the ongoing crisis to the attention of the general public, reporting the story of Nick Lardieri, a young father struck by silicosis at the age of 35.5 Under public pressure, the Minister for Jobs and Industrial Relations prohibited unprotected dry cutting of the artificial stones in September 2018. The labour inspection body audited 138 companies known to use artificial stone and issued 552 notices related to inadequate prevention and absence of health surveillance for workers.

The Queensland state government, meanwhile, started a screening programme of artificial stone workers. The results were alarming: one in eight of the screened workers already had silicosis without knowing it. Moreover, 15 of these men were diagnosed with the most severe form of silicosis, called progressive massive fibrosis, which has a very poor prognosis. Most disturbing is the fact that in many reports the average age of the diagnosed workers was under 40; they had developed the disease after only 10 to 15 years of working as a stonemason. We in fact see silicosis developing in these workers much quicker than what is observed in workers in other sectors such as mining. The youngest worker diagnosed was bare- ly 23 years old and had spent just six years working with artificial stone.

The urgent need for action

Many artificial stone workers have been exposed to hazardous concentrations of silica for years without appropriate protection; apparently nobody was aware of it until enough dust had built up in some workers’ lungs to cause severe forms of silicosis and make the problem visible. This means that prevention has been failing at multiple levels. The manufacturers must take responsibility for producing and marketing silica-containing artificial stone without prior risk assessment and without providing adequate information to workers and small stonemason companies. Actors responsible for workplace prevention, meanwhile, such as occupational health services, were unaware of these working conditions because they do not often make visits to such small companies. In many cases, health checks are not being conducted among silica-exposed workers, even in countries where it is a legal obligation.

We thus need to act, and quickly, to improve prevention in this industry. Simple dust masks are totally inadequate for protecting workers. Local exhaust ventilation and water suppression can reduce exposure to dust, but studies have shown that this does not reduce concentrations of respirable crystalline silica to non-hazardous levels. This means that we should seriously consider going a step further and banning high-silica content artificial stones, an approach proposed by the CCOO and by several lung specialists. Artificial stone can be made with alternative fillers with lower silica content such as recycled glass or natural stones. A legal prohibition of dry-cutting, as has been done in Queensland, can support pre- ventive action, but such measures only make sense if they can be enforced by adequately staffed labour inspections, which is not the case in many countries.

Besides prevention, it is important that screening be organised for workers that have already been exposed. The Australian experience has shown that if no screening is done, the problem can stay hidden for many years and workers are only diagnosed in a late stage of the disease. If you don’t actively look for silicosis, you will not see it. In October 2019, the Royal Australian and New Zealand College of Radiologists released their new guideline, confirming that CT scans, now widely accessible in many countries, should be the basis for screening these workers.

Many family doctors and lung specialists seem to have "forgotten" about the disease, leading to a lot of misdiagnoses or delays in reaching a correct diagnosis. Awareness must be raised about the current outbreak. Ideally, doctors should have access to (historical) exposure data from each individual worker that consults them. Although this is technically feasible, there is not one European country who has such a national system in place.

We still don’t know the real global extent of this problem, but the tragedy of workers, and particularly young workers, falling ill and dying from an entirely preventable disease should be a wake-up call that drives all actors involved to take action•.

KU Leuven

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A global outbreak of silicosis in an unexpected industry