Silicosis – a fatal disease where the silica dust from granite, sandstone and other rocks effectively turns lung tissue to stone – is not a new problem. The UK government first considered lung disease caused by silica dust for compensation in 1907.

A 1917 Home Office report authored by W Sydney Smith, an HM Inspector for Dangerous Trades, and Edgar L Collis, an HM Medical Inspector of Factories, recommended workers making silica bricks for furnaces should be protected from silica by ventilation and dust collection, wet working, enclosures and “suitable respirators.”

These measures were intended to address to worrying rates of ‘fibroid phthisis’ – an archaic term, like consumption, for tuberculosis – in silica-exposed workers. However, it was later realised most of these cases were probably not a bacterial disease at all, but silicosis, a dust disease.

‘Silicosis’ only became a generally accepted term in 1930, by which time, a 2015 paper in the American Journal of Industrial Medicine notes, it  “was well on its way to take its place as the most lethal and sustained epidemic of occupational disease in the 20th century.

Once you’ve got it, there is no escape. Silicosis is progressive, so will continue to spread, inflaming and hardening the lungs, even after dust exposure stops.  It is incurable.

And after a period when cases in key industries like mining fell, silicosis is making a comeback.

Dust enough?

Over a century after the government first acknowledged it was an occupational disease, the UK is now far behind best practice on silicosis recognition and prevention, with evidence both exposure standards and systems for identifying cases may be dangerously lax.

A January 2023 report from the All Party Parliamentary Group for Respiratory Health urged the Health and Safety Executive (HSE) to look at “the data and technology needed to allow the UK to reduce the WEL [workplace exposure limit] for work with silica to 0.05mg/m3.”

It was a belated recognition from MPs that the UK’s 0.1mg/m3 standard may not be sufficiently protective. HSE admits there will be six times more silicosis cases if it sticks at this level, but has told Hazards repeatedly it has no intention of lowering it.
Australia and the US, by contrast, have both completed multi-year consultations and introduced the more protective standard of 0.05mg/m3. In three years, Australia intends to follow global best practice and shift to 0.025mg/m3.

A whole new threat

There is another reason for caution. Engineered stone – an artificial stone widely used in kitchen countertops made by combining silica dust with resins and pigments and typically with much higher silica content that natural stone – has been linked with alarming new, rapid-onset, outbreaks of silicosis in the US, Australia, Israel and elsewhere.

Exposed workers have developed the condition younger and faster, some requiring life-extending lung transplants in their 20s. One in four stonemasons in Australia have been found to have silicosis. This prompted the Australian government in December 2023 to announce it would introduce a ban on all engineered stone (Hazards 164).

The US, which has seen outbreaks of silicosis in California and cases emerging in several other states, had in September 2023 introduced an ‘enhanced enforcement’ programme.

In December 2023, California introduced its own temporary emergency standard, tightening silica exposure controls and reporting requirements on silicosis cases, by both employers and healthcare providers. The California Department of Industrial Relations announcement noted the state authorities had “identified 95 cases of workers developing silicosis since 2019, 10 of whom have died from the disease.” It added: “The workers most at risk are those who cut artificial stone countertops” [see: California adopts emergency standard].

The UK is home to the largest engineered stone factory in Europe. Thousands of companies produce engineered stone worktops. One major supplier, Caesarstone, lists 138 suppliers in the UK. In 2020, sales rose by 75 per cent according to industry data.

ROCK BOTTOM  This botch up outside a Yorkshire factory producing engineered stone worktops is not the sort of “well-engineered” system to deal with silica dust and slurry experts say is necessary to reduce the risks of fatal lung disease. See: It’s silica, but not as we know it

While engineered stone may be doing well in showrooms, its possible impact on workers’ lungs concerned Baroness Bennett, who as Natalie Bennett was previously leader of the Green Party.

“Estimates suggest that, in the UK, 1,000 people a year die from silicosis as a workplace disease and many more suffer from debilitating conditions – not just stonemasons but construction workers, engineers and agricultural workers,” the Baroness said in a 15 January 2024 House of Lords debate.

“Surely the government should at least look into this further and get more data on a problem on which Australia, which is broadly comparable to us, has found it crucial and essential to act.”

No bodies

The response from the UK government was unequivocal.

Tory peer Viscount Younger, a parliamentary under-secretary of state at the Department for Work and Pensions (DWP), told the Lords “the Health and Safety Executive, HSE, is not currently considering restricting the use of engineered stone. In contradiction to what the noble Baroness, Lady Bennett, said, our information is that nobody has suffered any long-term exposure to silicosis.”

But three miles down the road, at London’s Royal Brompton Hospital, doctors were seeing things differently.

“Since mid-2023, we have started to see patients in the UK with this disease which is predominantly affecting younger men cutting artificial stone worktops in environments without sufficient protection and ventilation,” said Dr Johanna Feary, an honorary respiratory consultant in occupational lung disease at the hospital.

She told Hazards her team had “only seen a small number of cases to date,” but like the Australian cases she said they were in young workers and had developed rapidly. “We certainly have cases with less than 10 years exposure and advanced disease,” she said, adding her full findings would be published “in a few months.”

These cases discredit Viscount Younger’s assurances in parliament that safer work methods and a better regulatory system have ensured “nobody” in the UK has been harmed by engineered stone-related silicosis because the UK has “a mature regulatory model that combines targeted inspection activity on high-risk activity, communications activity and working with stakeholders.”

In fact, the emergence of this new aggressive, rapid-onset form of silicosis has occurred at the same time the UK has seen a sharp decline in the number of HSE frontline inspectors and the numbers of inspections and investigations HSE undertakes, including of priority workplaces (Hazards 162).

Invisible dust

There are three possibilities to consider. The first, the government assurance in January 2024 that there are no bodies in the UK, can be dismissed because of the silicosis cases linked to engineered stone identified at Brompton Hospital.

The second is the UK’s enforcement of dust controls is so superior to that in the US and Australia and elsewhere, the country has escaped the worst effects of a new and extremely potent cause of silicosis.

The third is the cases are there and have been missed.

STONE DEAD  Silica is the second most dangerous exposure for construction workers after asbestos, says HSE. But engineered stone, used in kitchen worktops, is a new and far more ‘lethal variant’, experts have warned.

There is good reason to believe what Baroness Bennett described as remarkable “complacency” on the part of the government might explain how an occupational health tragedy has remained largely out of sight and unaddressed.

Despite being a ‘prescribed’ industrial disease with sufferers eligible for state industrial injuries compensation, only 30 silicosis cases were assessed in the UK in 2022, and just 25 in 2021. But that doesn't mean the cases aren’t there.

It was only in 2015 that Australia saw its first cases of silicosis related to engineered stone. Since then, Australia has seen about five thousand workers diagnosed with the condition. In the US, it took a 2019 review of hospital silicosis discharge records to identify its first case linked to engineered stone. The worker had died in 2018 aged 38.

In March 2024, the British Occupational Hygiene Society (BOHS), calling for immediate action to address “an old problem in a new and nasty guise,” highlighted the diagnosis problem. BOHS president Alex Wilson noted: “Sadly, there is reasonable probability that there are more cases that have not been detected or reported. Accurate diagnosis of silicosis is difficult and it can easily mistaken for a more common complaint, sarcoidosis, for example.”

Lord Hendy, a Labour peer speaking in the Lords debate, noted, “one of the problems with silicosis is that it is not necessarily diagnosed by doctors and recorded on death certificates. That is because it is not a well-recognised condition apart from among experts.”

This has been borne out in a slew of recent studies. In a paper published on 23 July 2023 in the journal JAMA Internal Medicine, researchers from the University of California San Francisco (UCSF) and University of California Los Angeles (UCLA) described “the largest US study of this emerging health crisis.”

Jane Fazio, a pulmonary specialist at Olive View-UCLA Medical Center and co-author of the study, commented: “Increasing case counts of silicosis among stone fabricators over the last 10 years and accelerated progression of disease transforms the paradigm of an all-but-previously-forgotten disease in the US.” She added: “Our study demonstrates severe morbidity and mortality among a particularly vulnerable group of young underinsured and likely undocumented Latino immigrant workers.”

Study co-author Sheiphali Gandhi said: “Our paper raises the alarm.” The UCSF pulmonologist added: “If we don’t stop it now, we’re going to have hundreds if not thousands of more cases. Even if we stopped it now, we’re going to be seeing these cases for the next decade because it takes years to develop.”

A related JAMA Internal Medicine editorial examined the overall evidence and considered why large numbers of cases of a ‘lethal variant’ of silicosis in engineered stone workers came to be missed.

It concluded a silicosis diagnosis is often missed or delayed, which may be due to the “variable clinical presentation” or a lack of clinician awareness of occupational diseases. The editorial added an additional problem was the absence of systematic medical surveillance of engineered stone workers in the US or mandated reporting of cases.

Both factors are likely to have affected the UK’s ability to spot outbreaks. UK employers are not required by the RIDDOR regulations to report cases of silicosis. We do know the UK silica standard of 0.1mg/m3 is not protective. HSE admits at this level of exposure to silica dust over a working lifetime, 30 in every 100 workers exposed to silica dust from natural stone will develop silicosis.

But this isn’t natural stone. The dust created by engineered stone seems to be both more potent in the lung and more hazardous in the air.

Key references

• Compensation for industrial diseases. Report of the Departmental Committee for Industrial Diseases: Minutes of evidence, appendices, and index, HMSO, 1907. Manufacture of silica bricks and other refractory materials used in furnaces, with special reference to the effects of dust inhalation on the workers. W Sydney Smith, an HM Inspector for Dangerous Trades, and Edgar L Collis, an HM Medical Inspector of Factories, Home Office, HMSO, 1917.
• Rosental PA, Rosner D. and Blanc PD. (2015), From silicosis to silica hazards: An experiment in medicine, history, and the social sciences. Am. J. Ind. Med., 58: 3-5. https://doi.org/10.1002/ajim.22501
• Improving Silicosis Outcomes in the UK, All Party Parliamentary Group for Respiratory Health, January 2023.
• Silicosis in stone fabrication workers. Morbidity and Mortality Weekly Report (MMWR), 27 September 2019 / 68(38);813–818.
• Fazio JC, Gandhi SA, Flattery J, and others. Silicosis Among Immigrant Engineered Stone (Quartz) Countertop Fabrication Workers in California. JAMA Intern Med. 2023;183(9):991–998. doi:10.1001/jamainternmed.2023.3295. Published online July 24, 2023.   
• Hua JT, Rose CS, Redlich CA. Engineered Stone–Associated Silicosis—A Lethal Variant of an Ancient Disease. JAMA Intern Med. Published online July 24, 2023. doi:10.1001/jamainternmed.2023.3260.
  
  

It’s silica, but not as you know it

Australia’s decision to ban engineered stone came after it heard evidence that two of the key preventive measures promoted by HSE for work with silica – exhaust ventilation systems and wet working – may be dangerously ineffective with the silica dust generated when grinding, sanding or cutting engineered stone.

Kate Cole, chair of the external affairs committee of the Australian Institute of Occupational Hygienists, who gave evidence to SafeWork Australia’s silica enquiry, commented: “Wet cutting may not be protective of secondary exposures unless really well-engineered systems are available to contain and extract dust from dried slurry, for example.

“And as it stands, wet cutting alone is not enough to reduce exposure to below our workplace exposure standard in Australia, which is 0.05mg/m3.”

She added differences in the dust generated when working with engineered stone made it more dangerous than that seen in more familiar work with natural stone.
“The type of emissions from engineered stone are qualitatively different to that from natural stone,” she said.

“And these differences include things like the chemical composition, so organic resin and pigments, particle size, particle charge, crystalline silica polymorphs. The peer reviewed literature suggests that these components may contribute to the type of accelerated silicosis seen in workers exposed to engineered stone dust.”

She said “the size of dust generated when cutting into engineered stone… it’s at nano scale. It’s less than 0.1 micron. So, we’re talking like almost 80 days for a 0.1micron particle to settle.” She said the “fine and ultra fine dust…  it is very hard to control it.”

At least some of the dust will remain in the air for days or weeks, meaning workers are “exposed because of the long settling time for very small particles which aren’t being captured at the source to settle.”

She said this makes resuspension of settled dust an added problem.

California adopts emergency standard

California’s Occupational Safety and Health Standards Board has approved an emergency temporary standard on respirable crystalline silica to protect workers from silicosis. The standard came into effect on 29 December 2023.

State regulator Cal/OSHA proposed the emergency temporary standard to protect workers in the stone fabrication industry from silicosis. It says workers who breathe in silica particles can develop silicosis — an incurable, progressive disease that causes serious and fatal health effects. The workers most at risk are those who cut artificial stone countertops.

The California Department of Public Health (CDPH) has identified 95 cases of workers developing silicosis since 2019, 10 of whom have died from the disease.

The emergency temporary standard includes important requirements to protect workers engaged in high-exposure tasks such as cutting, grinding, polishing and cleanup of artificial stone containing more than 0.1 per cent crystalline silica and natural stone containing more than 10 per cent crystalline silica.

On reporting, the new standard dictates that employers must report employees with confirmed silicosis or lung cancer to Cal/OSHA and CDPH. Healthcare providers contracted by employers to evaluate their employees must also report confirmed silicosis cases to Cal/OSHA.

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DUST TO DUST

They’re everywhere. Engineered stone kitchen countertops look good and cost less. But there’s a catch, says Hazards editor Rory O’Neill. The workers making them are being struck at frightening speed by lung-destroying silicosis. In parliament, the UK government insisted “nobody” has been harmed. But down the road, hospital lung specialists are telling a different story.