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Safeguard OSH Solutions - Thomson Reuters

Safeguard OSH Solutions - Thomson Reuters

Safeguard Magazine

Kitchen consequences

DR GRAEME EDWARDS answers questions on the destructive outbreak of silicosis in Australia, prompted by the fashion for engineered stone kitchen benchtops.

Silicosis is a scar reaction in the lungs, caused by breathing in very fine dust particles, known as respirable crystalline silica. This type of dust is created when quartz is fractured by high speed mechanical processes such as using saws, drills and angle grinders.

Traditionally, silicosis was associated with quarrying, mining and stonemasonry industries, but one of the worst epidemics was associated with the fashion industry when stonewashed denim was the rage. The cloth was artificially aged in a factory in Turkey by sandblasting the fabric in such a way that it eventually killed over 90% of its workers.

How has the engineered stone silica exposure situation emerged in Australia?

Six factors have combined to create the situation we are now seeing. On the commercial front:

  • • 
    The rapid increase in the number of workers exposed, due to the rapid market penetration of engineered stone as a commercially valued bench top in Australian kitchens.
  • • 
    Limited regulatory surveillance to highlight to employers the necessary safe procedures to protect engineered stone workers.
  • • 
    The increasing number of people using extremely hazardous work practices, particularly three to ten years ago (due to the very forgiving nature of the product, which meant it could be fabricated by relatively unskilled people who didn’t have extensive training as stonemasons and who therefore didn’t know how to handle the hazard).

And on the medical front, we were better equipped to detect the disease:

  • • 
    Increasing sensitivity within the disciplines of occupational and environmental medicine, respiratory medicine, and radiology to recognise the features of the inorganic pneumoconioses in Queensland: Coal Mine Workers’ Pneumoconiosis (Black Lung Disease), mixed dust pneumoconiosis, and the various types of silicosis. These skills were not prevalent in other parts of Australia.
  • • 
    The respiratory physicians were reporting seeing an increasing number of cases presenting late in their clinical course, with increasing numbers requiring lung transplants.
  • • 
    Health monitoring examinations conducted by a single specialist work-related injury clinic on the Gold Coast, Queensland.

What is the scale of the damage being done to workers in that industry?

The true prevalence is unknown because the research has not been done. On 23 August 2018, of the first five people attending our clinic for health monitoring, four were found to have silicosis, and so I notified the regulatory authorities in Queensland that we might be seeing a significant problem.

By 5 September we had completed the assessment of all 35 employees from two businesses; 12 had silicosis. This gave a crude prevalence rate of 30%. Nearly one in three workers had the disease.

By the time about 100 medicals had been completed (not all by us) the rate was still around 30% and the cases being recorded by WorkCover Queensland were growing. Consequently, the Queensland Government announced its initial response on 18 September.

Since then, the numbers seem to have remained between 20 and 30% of the high-risk workers. If you dilute the number by including low-risk workers, the problem does not appear to be as bad. That is the problem we were seeing in NSW.

By 5 December 2018, 66 cases had been detected in Queensland.

What kind of symptoms do exposed workers suffer from?

Unfortunately, workers do not manifest any symptoms even with significant disease. It is why health monitoring programs, based on people developing symptoms, have failed to protect workers. By the time symptoms start, the only current treatment is to avoid further exposure and wait until the disease progresses to needing a lung transplant. Lung transplants occur when the air hunger is so great, you can’t do anything other than struggle to breathe.

Early symptoms of late stages of the disease are subtle, little things like: “I can’t chase the kids like I used to”, “I can’t go surfing anymore because I can’t hold my breath when I’m in the water”, or “I get to the top of the stairs and I have to stop and catch my breath”.

Initially, stoic workers just shrug off these symptoms. They might be treated as a virus as there is not much to find, but once the disease progresses to being evident on a standard chest x-ray, it is too late. The damage has been done. We have new possible treatments recently approved for clinical trials in Australia, but we don’t know yet if they will work.

What kind of interventions are happening or being proposed to reduce/eliminate that exposure?

On 18 September 2018 the Queensland Government announced a complete ban on uncontrolled dry processes – cutting, drilling and shaping. Appropriate wet processes can substantially reduce the production of the tiny dust particles that get down into the deep parts of the lung. The big dust particles that you see in the air are not the ones that do the harm. They land in your upper airways and can be more readily cleared from the body. While such dust particles can cause other problems, they don’t usually lead to a problem that will kill you.

Additionally, local exhaust/extraction ventilation is recommended to capture the dust or slurry. From a clinical perspective this should be mandatory.

Finally, half-face powered air purified respirators should be used as the minimum respiratory protective device. While negative pressure half-face respirators are technically adequate, very poor compliance with their correct use, and their respiratory protective failure rates, mean they are inadequate to provide reliable protection of the at-risk worker.

How is the engineered stone industry responding?

The employers with good intent are doing what they can to transition to safe work practices but there is no industry association to guide and inform its members. Regulatory authorities are promoting good work practices and in some jurisdictions have dramatically increased their inspection of workplaces (I can’t tell you what is happening in New Zealand).

The importers and distributors are doing what they can to protect their market share and their profitability, so they are also promoting the transition to safer work practices.

Why has this problem emerged now?

It takes time to accumulate sufficient silica dust in the lungs. The higher the exposure, the shorter the time to develop the disease. We are only seeing it now because of the numbers and timing.

The product only hit Australian shores in about 2000, so the numbers needed to grow with the adoption of the product as a preferred kitchen benchtop. It is a good quality product, easier to work with and cheaper than natural stone, so it is not surprising it has been adopted by the market. However, these workers were exposed to bad work practices seven to ten years ago, and hence are developing the signs of the condition on ILO chest x-rays and high-resolution CT scans now.

What other industry sectors might also be exposing workers to silica dust?

Any sector that works with sand, stone, or quartz-containing substrates carries some level of risk. Classically, it is the mining, quarrying, building and construction industries, hence the keen interest of the Construction Forestry Maritime Mining Energy Union in Australia.

The nature of the substrate you are working with, and how you are handling the product, will determine the rate at which you will accumulate sufficient dust in the lungs to cause harm. How much dust is needed to trigger disease is one of those “known unknowns”. By studying the exposure patterns of the high-risk workers we are currently seeing, we hope to find some answers to inform a Code of Practice for the kitchen benchtop industry in the first instance, and then for any worker who might be exposed to respirable crystalline silica.

A key problem with engineered stone is the very high concentration of quartz (over 90%) fabricated using hand-held high speed mechanical devices. There is some thought that the nature of the resin used to bind the quartz may also be important, but at this stage we just don’t know.

Given the industry factors, there is no reason to suspect the same problem will not happen in New Zealand. Simply put, if you don’t look for it in your high-risk workers, you won’t see it for another few years when their exposures mount. That’s when the cases of disease will be diagnosed by the respiratory physicians, but for many workers being exposed now, it will be too late.

Queensland-based Dr Graeme Edwards is a senior consulting physician in occupational and environmental medicine.

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