Dust that can enter the nose and mouth during breathing is referred to as ‘total inhalable dust’. Some dust may consist of larger or heavier particles that tend to get trapped in the nose, mouth, throat or upper respiratory tract where they can cause damage.
Dust particles that are small enough to be breathed into the lungs are called ‘respirable dusts’; these dusts can build up in the air spaces in the lungs and can lead to lung damage.
The build up of any dust in the lungs could produce lung damage with inflammation and eventually fibrosis (scar tissue). This could lead to breathing impairment. These conditions usually develop slowly, so symptoms may not appear until severe irreversible changes have taken place.
Some dusts are well known for their ability to produce serious lung diseases of this type, eg respirable crystalline silica (RCS) can cause silicosis and also lung cancer. Chronic effects of dust in the lungs are usually permanent and may be disabling, so prevention of the onset of disease should be given the highest priority.
Certain dusts, eg dusts from grain, flour, wood, reactive dyes and proteolytic enzymes are respiratory sensitisers which can cause occupational asthma (attacks of coughing; wheezing and chest tightness), rhinitis (runny or stuffy nose) and extrinsic allergic alveolitis (symptoms can include fever, cough, worsening breathlessness and weight loss).
Some dusts can cause ulceration of the skin and irritation or skin sensitisation can be caused by dusts such as epoxy resins, rubber processing chemicals, wood dust and fibreglass and can lead to dermatitis.
Dust particles produced during the cutting, grinding and drilling of materials can cause eye damage/irritation, and some dusts may cause eye damage/irritation due to their chemical nature.
Some inhaled dusts can become trapped in the mucus that lines the respiratory tract. This mucus tends to be either spat out or swallowed. Inhaled dusts can get into the digestive tract, where they can cause local effects such as gastrointestinal tract irritation. Alternatively, they can enter the bloodstream and produce effects in other organs and tissues.
Dusts may also find their way into the digestive tract via hand-to-mouth contact so ensure that employees maintain good standards of personal hygiene, and consider whether eating and drinking should be prohibited in the workplace.