Asthma - what is it?

Asthma is a chronic, inflammatory, non-infectious lung disease characterized by recurrent breathing problems. During normal breathing, air flows freely in and out of the lungs. But, during an asthma attack, the lining of the airways swells, muscles around the airways tighten and mucus clogs the tiny airways in the lungs, making breathing difficult.   Serious attacks can be fatal.

People with asthma have airways that narrow more easily than non-asthmatics and are usually allergic to inhaled allergens. The causes of the airway abnormality and its relationship to being allergic are not known. Many things can set off an asthma attack including exposure to tobacco smoke; air pollution; chemical irritants; allergens (eg dust mites, protein particles shed by cats and dogs and pollen); exercise; strong emotional expressions; viral infections; and some drugs. Different people react to different things. 

The number of asthma sufferers is increasing around the world - more than 300 million people suffer from asthma. Australia has a very high incidence - over two million people have asthma. It affects one in four children, one in seven adolescents and one in ten adults. For more information, see Bulletin 59 (April 2008): Occupational asthma in Australia [pdf], produced by the Australian Institute of Health and Welfare.

Unions believe that in Australia not enough attention is paid to the link between asthma and work .  People who already have asthma may find that certain substances at work trigger it (for example breathing in dust, fumes or  tobacco smoke).  Some substances can cause previously healthy workers to develop occupational asthma - these are called 'respiratory sensitisers'. 

Who is at risk?

The top eight causes of asthma at work, and the workers most at risk of exposure are:

  • Isocyanates - paint manufacturers, spray painters, other metal or electrical processors, makers or repairers (mainly vehicle manufacture and mechanics), plastics workers, printers;
  • Flour/grain - bakers, other food processors, farmers, farm workers;
  • Wood dust - wood workers;
  • Gluteralderhyde (used as a disinfectant) - nurses, non-metal or electrical processors (mainly darkroom technicians), other professional clerical and service occupations (mainly radiographers);
  • Solder/colophany - welders, solderers or electronic assemblers, other metal or electrical processors, makers or repairers;
  • Resins and glues - metal and electrical processors, makers and repairers, construction and mining, other non-metal or electrical processors, makers or repairers, chemical processors;
  • Latex - nurses and health workers, laboratory technicians; and
  • Laboratory animals.

Other causes include environmental tobacco smoke and some other chemicals. There are over 200 known respiratory sensitisers, and more are being identified all the time. A recent article in the European Respiratory Journal, for example, reported that chloramines, chemicals used in indoor swimming pools, could cause occupational asthma. And Canadian researchers, in a June 2009 study, demonstrated a strong link between work-related symptoms of asthma and dermatitis among cleaners. 

What are the health effects of asthma?

Asthma symptoms include shortness of breath, coughing and wheezing, and tightness of the chest. The symptoms can vary from hour-to-hour, day-to-day, week-to-week and over months. They are often worse at night and in the early hours of the morning. The severity of asthma varies from individual to individual. Some sufferers have occasional symptoms (for example after strenuous exercise); others have symptoms that interfere with daily life; while others still have a very severe disease that can exclude them from normal work activities.

Asthma attacks can be fatal, despite the fact that there is adequate treatment of the condition.

Exposure to chemicals in the workplace can lead to many illnesses and the condition of occupational asthma provides a good example of the impact of health, work capacity, normality of life and financial security.

ASTHMA is a very common condition in Australia there are estimates that 10 - 20% of the illness is related to workplace exposures.

ASTHMA is a condition of increased responsiveness of the air passages of the lungs with widespread narrowing of the passages, inflammation and showing in the person as cough, shortness of breathe and wheeze (whistling or noisy breathing).

ASTHMA occurs in episodes or can be present daily, and treatment in general asthma relies on avoiding things and situations that make it worse, and the use of medication including preventers (to reduce and control inflammation) and relievers (to assist in widening the air passages).

OCCUPATIONAL ASTHMA is asthma occurring as a result of work related exposures. There is also cough, shortness of breath and wheeze as a result of air passage narrowing and inflammation.

OCCUPATIONAL ASTHMA can come on slowly or rapidly, and so the person who develops occupational asthma may not associate the illness with work.

However if there is an awareness of what chemicals and substances may result in occupational asthma in the workplace there is a better chance of avoiding the development of the illness.

OCCUPATIONAL ASTHMA can result from chemical irritation and from chemical sensitisation (allergic type reaction) of the lungs and so control of respiratory irritants and hazardous substances with the notation s (sensitiser) will reduce the likelihood of the illness developing.


  • Shortness of breath eg puffing while climbing stairs, difficulty getting breath, increased difficulty with exercise
  • Cough eg cough that won't go away
  • Wheezing or whistling noises in the chest

All of these effects do not have to be present to raise the suspicion that asthma has developed.

Sometimes the effects develop very slowly, so that it is difficult to pick when the problems first started, but at times there is sudden severe illness.

How can Occupational Asthma be picked up?

Occupational asthma can show up with cough, wheeze, shortness of breath (or any combination or single effect)

  • Worse at work
  • Worse in contact with particular chemical(s)at work
  • Worse at work in a particular area at work
  • Worse at work when a particular process or batch is running
  • Easing during the weekend or time off work
  • Easing or disappearing during holidays or annual leave
  • Worse first thing on Monday morning
  • Worse when first back at work after a break
  • Worse at night after work (early evening or late)

Later in the illness there can be no particular pattern related to work, but symptoms present all the time.

At times other chemical or irritants can also cause the asthma to get worse.

What is done if Occupational Asthma develops?

  • Firstly, prevention is best
  • If suspected see a doctor and point out that this may be work related
  • Take the MSDS (Material Safety Data Sheet) to the doctor if a chemical or process is suspected to be the cause.
  • Seek further help if necessary
  • Testing of the lung function is required
  • Treatment of the asthma is required
  • Control of the substance(s)at work is required once recognised
  • At times removal from the workplace is necessary
  • Some people develop severe asthma and cannot work in same industry again.

There may be many people in Australia with symptoms related to chemical exposures in the workplace.  These symptoms include rashes, palpitations, cramps, pain in joints, and many more.  Symptoms that are suspected to be related to exposure to chemicals at work need to be assessed by a doctor.  Information such as SDSs (Safety Data Sheets)/MSDSs (Material Safety Data Sheets), to provide information about the exposures, is very important.

last amended February 2015