Working With Dust

The law requires that a systematic approach should be taken when employees are subjected to dusts at work. Of course, the type of dust can vary enormously depending on the working environment but there are some general precautions that can be taken.

Effects of Dust

Most large particles of dust are stopped from reaching the lungs by mucus in the upper respiratory tract – nose and throat. Particles of dust that evade rejection by the respiratory tract can penetrate further into the lungs. Another protective system exists for smaller particles. Macrophages (special defence cells in the body) help to break down particles that have entered the lungs, rendering them harmless.

Unfortunately, not all dusts can be broken down. Many inorganic dusts, such as asbestos, silica and coal present a problem for the lungs. Cells attack these dusts but, since they cannot be easily broken down, fibrous tissue is laid down around the dust particles. Over many years of exposure, fibrous tissue can accumulate, which then affects lung function. Severe breathing difficulties can result and cancer of the lungs is also a possibility.

Many organic dusts, for example grain, present less of a problem, although there are many examples of specific dusts causing health concerns. Animal microbes and spores from fungi can be harmful to health, requiring medical attention and treatment.

Legislation

There is a specific piece of legislation that deals with dusts in the workplace, the Control of Substances Hazardous to Health Regulations. These regulations require employers to:

• Assess the risks to health caused by exposure to dust;
• Take steps to ensure that exposure is prevented;
• If exposure cannot be completely prevented, take steps to control the level of exposure;
• Train employees in the hazards, risks and control measures that have been put in place to reduce the exposure.

Depending on the type of dust present, employers may also have to measure and analyse the dust and to monitor the environment to ensure levels are within acceptable limits.

Assessing the Risks of Dusts

The following questions need to be answered to help make an assessment of the risks of dusts in the workplace:

• Who is exposed?
• How often and how long are they exposed and how often?
• Why are they exposed?
• What type of dust are they exposed to?
• What control measures are in place to reduce the level of dust?

The fourth point is an important one. It is impossible to make a proper assessment of the risks unless the exact type of dust is known. Depending on the type of dust, sampling may need to be taken for analysis. In most cases, for example wood dusts, sampling is not necessary and a less quantified judgement can be made.

Controlling the Hazard

Once information is gathered about the type of dust and the nature of exposure to the dust, control measures can be considered.

• Eliminating the hazard is the best method of control. However, this is not always practical because it may involve discontinuing a process or operation.
• Substitution is the next best method of control. This involves using a different substance or material to do the same job. For example, the dust from red wood is known to be carcinogenic, but white wood presents much less risk.
• Containment of the process is a good idea because it helps to prevent the general workplace becoming contaminated.
• Improving maintenance of plant and equipment can significantly reduce the amount of dust that is expelled into the environment.
• Methods of work can help to reduce the level of dust that escapes into the environment. By providing training for employees on how to handle dust-producing equipment, a greater awareness of the hazards and risks can be appreciated. Simple changes to working methods can help to increase workplace cleanliness.
• Ventilation control is often the last resort when it comes to reducing dust in the working environment. Special systems called Local Exhaust Ventilation (LEV) use extractor fans to raise dusts into ducting. Usually, ducts lead to collection bags where the dust can be removed for proper disposal.

It is important to remember that, although dust in the workplace can be a hazard, dust escaping into the atmosphere can also present problems. It is a legal offence to pollute the environment and dust is classed as a pollutant. So, regardless of the control measures that are employed, it is vital to ensure that nothing escapes from the working premises.