Dust danger

WE ALL understand contamination and its negative connotations, however what does it mean on a day to day basis for us as individuals and organisations? Contamination covers an incredibly broad spectrum of phenomena, ranging from relatively minor transient occurrences to devastating long lasting events. While contamination comes in multitudinous forms and the means of managing it are equally numerous, there are some broad categories into which we can categorise them based on either the form of the contamination, or the means by which it can affect us. 

One of the most prevalent forms of contamination encountered in the workplace, and also one of the most hazardous to health is dust.

What is dust?

Thousands of people each year suffer adverse health effects due to workplace dust exposure. This exposure can lead to chronic lung diseases ranging from Occupational Asthma, Chronic Obstructive Pulmonary Disease (COPD), Pneumoconiosis, and Cancer with thousands of new cases diagnosed each year in the UK.

Dust can cause deleterious health effects in a number of ways depending on its composition and size, including physically damaging the respiratory system, pathogens, radiological, and chemical damage.

Dust can be a particularly insidious contaminate, with the particles that are the most hazardous to human oftentimes invisible to the human eye; and with the health effects only becoming apparent many years later. 

Lead

Lead and its compounds are cumulative toxins that bioaccumulate over time and can have serious negative health implications for those exposed. Indeed, The Institute for Health Metrics and Evaluation (IHME) estimated that in 2017, lead exposure accounted for 1.06 million deaths and 24.4 million years of healthy life lost (disability-adjusted life years (DALYs)) worldwide due to the long-term effects on health. In the UK, the majority of exposure is in industries specifically focussed on lead, however the fourth largest sector for people under medical supervision for lead exposure is in demolition and construction. The specific Approved Codes of Practice (ACOPs) relating to the control of lead at work are detailed in HSE L132 which details what provisions are recommended, ranging from reducing the risk of exposure to mitigation methods, such as respiratory protection and filtration. For example, a high standard of personal hygiene plays a crucial role in controlling lead absorption. One method of achieving this could be by ensuring shower facilities are available, a mobile decontamination unit for example would ensure workers can be cleansed whilst ensuring that any potential lead contamination is captured by the filtration systems rather than being reintroduced to the environment.

Flour dust

It is perhaps easy to underestimate the potential hazards of flour dust, up to 100,000 people are potentially exposed to it every day in the UK baking sector, usually with no obvious side effects. Flour dust is what is known as a respiratory sensitiser, a substance which, when inhaled, can trigger an irreversible allergic reaction in the respiratory system also known as Occupational Asthma with symptoms such as wheezing, shortness of breath, runny nose, nasal congestion, eye irritation, and chest tightness. The HSE has set a Workplace Exposure Limit(WEL) comprising a long-term exposure limit of 10mg/m3 (averaged over 8 hours) and a short-term exposure limit of 30mg/m3 (averaged over 15 minutes). Due to its properties as an asthmagen, all efforts should be made to reduce it far below the WEL, indeed less than 2mg/m3 (averaged over 8 hours) is usually achievable. Fortunately, methods of control are available, ranging from reducing the production of dust, for example with dust reducing handling methods, the provision of appropriate respiratory protection, and methods of reducing the amount of dust in the air

Asbestos

Despite the use of asbestos-containing materials (ACMs) being banned in 1999, asbestos still poses a serious threat, especially to tradespeople, due to its previous prevalent usage. Despite improvements in managing it, it still kills on average 20 tradespeople a week due to the long latency between exposure to the microscopic fibres and onset of diseases such as asbestosis and mesothelioma. Working with asbestos can pose many dangers and many tasks can only be carried out by contractors licensed by the HSE following the Control of Asbestos Regulations 2012. If while carrying out any work you discover materials which you believe to be asbestos, stop work immediately. Put up a warning sign and ensure nobody enters the area. Report the problem to whoever is in charge and arrange to have a sample of the material analysed. If it does not contain asbestos then work can continue. If the material does contain asbestos then consult HSE guidance, such as asbestos essentials em1, which will offer further guidance on how to proceed.

Wood 

Exposure to wood dust can result in serious health problems, acting as respiratory sensitisers which can cause asthma - which affects carpenters and joiners four times more frequently compared with other UK workers and hardwood dust is particularly associated with nasal cancer. The Control of Substances Hazardous to Health (COSHH) Regulations 2002 require that you protect workers from the hazards of wood dust and WELs are in place for both softwood 5mg/m3, and hardwood dust 3mg/m3 (both based on an 8-hour time-weighted average). Methods of control, as set out in HSE WIS23, include dust extraction, also known as local exhaust ventilation or LEV, which should be specifically designed to meet your particular needs; where necessary respiratory protection should be provided with face fits carried out by a competent person. When cleaning up wood dust care must be taken not to disturb the dust such as by sweeping, a suitable vacuum, at the minimum, Class M, should be used. 

Concrete/silica

Concrete is near ubiquitous in the construction industry however its potential risk to health is often underestimated. High levels of concrete dust can be produced when cement is handled, such as when emptying or disposing of bags, scabbling or concrete cutting. Short term exposure to this dust can lead to irritation of the respiratory tract, and longer term exposure can lead to occupational asthma. Additionally, concrete and mortar can contain respirable crystalline silica (RCS). Inhalation of this RCS can lead to the development of silicosis or scarring of the lungs, which results in a loss of lung function and severe shortness of breath. High levels of exposure can ultimately prove fatal by inducing lung cancer; and very high levels can rapidly lead to illness. Breathing in RCS can also lead to COPD resulting in severe breathlessness, prolonged coughing and chronic disability and is a leading cause of death in the UK.

For those cases where the exposure can be predicted, one possible means of mitigation would be the practice of having mobile showers on site to ensure workers can wash themselves at the end of a shift ensuring that any lingering dust is removed. These have the advantage over standard showers in that they are under negative pressure, and filter the air inside before exhaust; additionally, the wastewater from the shower is also filtered, further reducing any potential release of contamination to the environment. The advantage of combined welfare/shower units means that the requirements for welfare facilities can also be met at the same time without needing additional equipment on site.

Hopefully this piece has highlighted that potential sources of contamination are often not readily obvious, and that care must be taken to ensure that all practicable methods of control are instituted to protect the health of both you, your employees and the wider public.

Kurt Greenall is business analyst at SMH Products. For more information, visit www.smhproducts.com