Dust and nanoparticles
Health and safety

The term ‘dust’ has no precise scientific meaning, but is usually defined as a solid which has been broken down into powder or fine particles. The size of the particles is just as important as the nature of the dust in establishing if it is hazardous. Generally, the most dangerous types of dust are those with very small particles which are invisible to the human eye, as is the case with fine powders. These types of particles are small enough to be inhaled but at the same time large enough to remain trapped in the lung tissue and not exhaled. However, some substances (e.g. asbestos) produce very coarse dusts with large particles which can also be dangerous.

Remember: substances can produce dusts with different sized particles — just because you can only see large particles of dust or granules doesn’t mean small ones aren’t present as well.

Nano-materials: Many modern processes use nano-materials. These are particularly dangerous as they can be absorbed directly into the bloodstream through the skin and through the lung membranes if breathed in. They should be regarded as dangerous to health regardless of the material they are made of. Normal protective equipment will not provide adequate protection and you must contact your laboratory before opening or attempting to sample such products.

Toxic dusts: These are generally produced when working with substances which are themselves toxic e.g. chemicals containing lead, mercury, chromium or toxic organic substances such as fentanyl and its analogues. If inhaled, they could damage your lungs or get into your bloodstream and be distributed throughout your body. Fentanyles and other synthetic opioids can cause very rapid respiratory depression and sedation. See Controlled Drugs.

Nuisance dusts: These may be generated by handling materials such as:

• flour/grain;
• pitch;
• tobacco;
• sugar;
• paper;
• dried foodstuffs;
• cement;
• sawdust;
• coffee beans and tea;
• carbon black (as in photocopier/printer toner).

These types of dusts are generally only irritating, but in concentrated form they can be hazardous to health. Hardwood dust is carcinogenic (see section 7).

In some areas you might come across cannabis dust during your work (e.g. in an official warehouse). This type of dust is not thought to be particularly dangerous, as it is not easily absorbed by the body and is generally in a low concentration.

Flammable dusts: Flammable dusts travel through the air in clouds and can easily be ignited, setting off a flash fire or explosion. They can be set alight by a spark or naked flame, or even by settling on a hot surface. When flammable dusts settle and are ignited, they can burst into flame or simply smoulder — long after the source of ignition has been removed. Following an explosion, flammable dusts can be spread over a wide area, increasing the risk of a serious fire.

It is highly unlikely that you will encounter any flammable dusts during your work.

You can encounter nuisance dusts almost anywhere. Some of the most common are:

• paper dust in mail-sorting offices and stationery stores;
• cement dust on building sites;
• various dusts at ports, inland clearance depots and trader’s premises;
• photocopier/print rooms.

You might also encounter toxic or flammable dusts in dangerous concentrations at places where bulk cargo is being loaded, unloaded or moved (e.g. grain, metal ores, coal, etc.).

Dusts generally cause damage to the lungs and respiratory system, but some types can cause cancer. The main diseases associated with inhalation of hazardous dusts are:

Benign pneumoconiosis. A disease caused when apparently harmless dusts are inhaled and deposited in the lungs to such an extent that they are visible in an X-ray. They cause no damage to the lung tissue and hence the disease is not disabling. This condition is most commonly associated with dusts from metals such as iron and tin.

Pneumoconiosis. A collective name for a group of chronic lung diseases caused by inhalation of particular mineral dusts. The term includes a number of diseases which are named after the dust which caused them. The best known are:

• asbestosis (from asbestos dust) — see asbestos;
• silicosis (from silica dust);
• talcosis (from talc dust).

Pneumonitis. Inflammation of the lung tissues or bronchioles mainly caused by inhalation of certain metal dusts. The symptoms are similar to pneumonia, but vary in severity, depending on which metal is inhaled. The most common causes are cadmium and beryllium dusts.

Mesothelioma of pleura. Tumour of the lungs, mainly caused by exposure to asbestos (see asbestos).

Lung cancer. This too can follow any exposure to asbestos (see asbestos).

For most types of dust, including nuisance dusts, exposure limits have been set in health and safety regulations. You should consult your national guidance and the EU legislation.

However, as you will probably have little control over the source of the dust in most cases, you must take every precaution to reduce the risks. You should:

• use a respirator or face-mask;
• if possible ensure the working space is well ventilated;
• If dust extraction equipment is available, ensure it is used;
• limit your exposure to the dusts;
• have regular health checks;
• leave the contaminated area straightaway if you feel any immediate symptoms.

Remember: you should only remain in a dusty atmosphere for the absolute minimum length of time required to do the job — even if you are wearing respiratory protection.