Dust at work can be a significant hazard if the risks are not properly identified and controlled. Employees in a wide range of business sectors including mines, quarries, foundries, textiles, mills, bakeries, or industries working with wood, leather and radioactive materials may develop ill-health after working in a dusty atmosphere.
Health problems associated with exposure to certain dusts include: silicosis, asthma, emphysema, mesothelioma and other cancers, allergies, skin and eye damage, blood disorders and nervous system damage.
Many dusts, including flour, coal, metal, and rubber, are combustible and possibly even explosive in certain circumstances (see fire safety).
Again, you need to know details about the process which generated the dust and the materials being used at the time before you can start assessing the risks. Once this information is to hand, more detailed information can usually be found on the HSE website by using their search tool and including either the material or your industry type in the search criteria.
Assessing the risks
When conducting a risk assessment for a substance in the form of a dust, the following questions need to be answered:
- Is the dust likely to pose a serious risk to health? This will definitely be the case where the material is known to be:
- carcinogenic (e.g. asbestos, most hard wood dust, etc.) or otherwise toxic, harmful or irritant; and
- respirable, i.e. below 10 microns in diameter and likely to remain airborne for some time. This type of dust is difficult to see under normal circumstances and can move with air currents, possibly moving the hazard some distance away from the point of generation.
The quantity and movement of respirable dust clouds can be demonstrated using a special dust lamp – for details see HSE leaflet MDHS82 The Dust Lamp.
- How much dust is being generated? This will depend upon many factors including the type, efficiency and proper use of any engineering controls (containment and/or local exhaust ventilation (LEV) etc.) used with the process. Apart from the hazards associated with respirable dust, there can be significant hazards from non-respirable dust including:
- slipping on dust deposited on the floor; and
- risks to eyes and skin from dust that:
- moves at high speed, particularly as the particle size increases;
- reacts with moisture; and/or
- settles, forming an abrasive layer.
Non-respirable dust can normally be easily collected as part of the normal cleaning process and measured by weighing, if required. Special methods have to be employed to determine quantities of respirable dust and these are detailed in an HSE leaflet MDHS 14/3 General methods for sampling and gravimetric analysis of respirable and inhalable dust. You may wish to consult a competent occupational hygienist on the benefits of using such a procedure beforehand.
Control measures
Commonly used and effective control measures for dust are containment and local exhaust ventilation (LEV). If you intend to use either of these methods of control, you will need to define a full specification in association with an occupational hygienist or other person able to provide competent advice, and a supplier of such equipment.
You will also need to make arrangements for regular inspections by nominated employees and, where appropriate, annual statutory examinations by a competent person, usually an insurance engineer.
Personal protective equipment
Personal protective equipment (PPE) should only be used as a last resort, in line with the hierarchy of control (see Prevention of control exposure above). If there is no alternative to using PPE, you should make specific arrangements to ensure that only masks or respiratory protective equipment (RPE) suitable for the type of dust is specified and used and that it is CE marked.
General purpose dust masks (sometimes called nuisance masks, comfort masks or hygiene masks) should not be used to protect against hazardous dusts, as their effectiveness is not known and the HSE has been warning against their use since January 2003.
Depending on the results of your risk assessments on dust, with regard to its type, quantity and controls used, it may be necessary to conduct regular monitoring of the workplace and/or health surveillance on the affected employees. If you are uncertain, discuss issues on monitoring with a competent occupational hygienist or health surveillance with an occupational health professional.