Last reviewed 17 September 2015
Workplace health experts believe that exposures to very fine dusts containing quartz, known as respirable crystalline silica (RCS), are not being managed as they should be and possibly brushed off as “just a nuisance”. In the following article, Vicky Powell examines how better compliance with silica standards in the UK could dramatically improve key worker health outcomes and why health and safety leaders are focusing their efforts on better controls of silica risks.
Understanding silica and its health effects
Fine dusts containing crystalline silica are found, most commonly, in the form of quartz in almost all kinds of rock, sands, clays, shale and gravel. Silica is also found in products such as bricks and concrete, as well as being used as filler in certain plastics.
Occupations with exposure to crystalline silica include brickworks, construction (when cutting or breaking stone, concrete or brick), foundries, potteries, quarrying, slate works, stonemasonry, tile manufacturing, and industries using silica flour to manufacture goods.
In the workplace these materials create dust when they are cut or sanded down, and where the dust is fine enough to reach deep inside the lungs, this is known as respirable crystalline silica (RCS). Significant exposure to RCS can cause great harm to health, including lung cancer and silicosis — the thickening and scarring of lung tissue caused by the inhalation of dust containing silica.
The main symptoms of silicosis are:
a persistent cough
shortness of breath
weakness and tiredness.
Silicosis can have significant clinical and life-threatening consequences including an increased risk of premature death from heart failure. Unfortunately, workers with silicosis are also at an increased risk of tuberculosis, kidney disease and arthritis. In addition, exposure to RCS may also cause chronic obstructive pulmonary disease (COPD), such as such as bronchitis and emphysema.
The Health and Safety Executive (HSE) reports that approximately 600 deaths per year are caused by lung cancer associated with exposure to RCS, with around 450 of these occurring from exposures in the construction sector. When other diseases attributable to silica are considered, the number of deaths has been estimated to be potentially as high as 1000 a year.
Lack of compliance
The leading research scientist and former President of the British Occupational Hygiene Society (BOHS), Professor John Cherrie, was recently quoted as saying, “There is widespread non-compliance with the respirable crystalline silica standard in the UK and in the rest of Europe. Our research shows that getting firms to work to a tighter standard would go a long way to help eliminate the health risks from these exposures.”
Writing in his blog, Professor Cherrie has highlighted research which indicates just how critical it is to try to improve the level of compliance from the currently estimated level of just 33% of workplace silica exposures achieving the occupational exposure limit (OEL) of 0.1 milligrams per cubic metre. Professor Cherrie has pointed out that if better compliance, of 90%, were achieved, almost all the cancer deaths from silica exposure could be prevented in the future.
Furthermore, on the subject of the limit of 0.1 milligrams per cubic metre, Mike Slater, a Chartered Occupational Hygienist and the immediate past President of BOHS, recently warned that even this should not be viewed as a "safe limit" given the fact that an estimated 2.5% of workers exposed to this concentration for only 15 years go on to develop silicosis.
It is encouraging to see that health and safety leaders are taking up the challenge on silica in a number of ways. Silica dust is one of the five key cancer risk factors currently being highlighted by the Institution of Occupational Safety and Health (IOSH) in its current No Time to Lose campaign on work-related cancer, along with diesel exhaust fumes, solar radiation, asbestos, and shift work.
IOSH recently published the results of a construction industry survey, conducted jointly with the Construction Dust Partnership (CDP), which found that workers feel the issue of construction dusts, including silica, needs more focus.
When asked what priority they think the industry currently puts on the control of construction dust risks, a total of 44% of workers answered “very little”. Only 12.5% of the workers surveyed said they felt dust was “a priority health issue”.
Commenting on the research, IOSH spokeswoman Jane White said, “The report clearly details that not only is the use of extraction and dust suppressant equipment not appropriately used, but the comments received also suggest that there is a confused picture about its availability, effectiveness and suitability for different tasks. There is a serious gap in information, instruction and training that we must rectify.”
Other research was highlighted earlier this year by BOHS as part of its Breathe Freely campaign to prevent occupational lung disease in the construction industry. A study, published in the journal Occupational Medicine focused in detail on six stonemasons, ranging in age from 24 to 39, who developed silicosis, one after just seven years in the trade.
Commenting on the research, BOHS said in a statement that it condemned the fact that young workers are continuing to develop silicosis despite it being an “entirely preventable” occupational lung disease.
Steve Perkins, Chief Executive of BOHS said, “This research study is hugely important because it highlights the devastating impact that exposure to hazardous dusts —- simply by carrying out the regular tasks of their trades — can have on young construction workers’ lives today."
Dr Alasdair Emslie, Immediate Past President of the Society of Occupational Medicine said, “The missed opportunity is that this is an old disease that we know how to control."
Prevention and controls — the “missing link”
Commenting on exposures to silica in the workplace, Phil Bates, a Chartered Member of IOSH, emphasised that silica dusts can be controlled.
He said, “To tackle the problem, you must first assess the situation. You need to look at your process where silica dust can be produced and determine which and how many workers are being exposed and what work tasks they are doing, as well as the equipment they are using, that are causing the exposure. You need to think about the frequency and length of time they are carrying out these tasks. And you should consider where they are working. All of these things will have an impact on the amount of exposure and the controls that might need to be used.
Highlighting silica exposure as part of BOHS’s Breathe Freely campaign, Mike Slater recently said, “For most of the common operations where workers are at risk from exposure to silica, there are control measures available that are usually relatively straightforward to implement.”
In a slide presentation, available on the campaign site, Mike Slater emphasised the critical role of prevention and control of exposure as the “missing link” in protecting workers from the risks associated with silica, with typical control measures being water suppression or extraction systems for tools (or both).
RCS is currently registered as one of the top issues on the future work programme of the new Workplace Health Expert Committee, recently put together by the HSE. In months to come, health and safety professionals may expect further action in the risk management of RCS, from both industry leaders and the authorities, as they seek to educate employers and workers that silica dust in the workplace should never be viewed as merely a nuisance.