Asthma is a disease of the airways. Symptoms include wheeze, cough and
chest tightness. The patient experiences difficulty in breathing.
Often the symptoms subside, only to reappear at a later date.
Occasionally symptoms deteriorate to the extent that the disease becomes
life-threatening. People can and do die from asthma.
Asthma is now recognised as one of the most important health issues in the United Kingdom. It affects between 5% and 10% of the population and it is believed to be on the increase.
Types Of Workplace Asthma
Asthma in the workplace can be of two main types.
- Work-aggravated asthma
- Pre-existing asthma made worse by exposure to
substances in the workplace.
- Occupational asthma
- Asthma caused by exposure to substances in the
The second type of asthma is of particular concern because one a worker has developed asthma due to exposure to a chemical, subsequent exposures (even of lower concentrations of that chemical) will provoke an asthma attack.In essence the worker has become sensitized (in an allergic or allergic-like manner) to the chemical.
Within the United Kingdom approximately 1000 cases of occupational
asthma are diagnosed each year by specialist doctors. This is believed
to be the tip of the iceberg - many more cases are likely to be missed.
Surveys in USA and Japan suggest between 5% and 15% of asthma is
work-related. It is probable that at least 5% of asthma in the UK is
also work related.
For a more detailed review of occupational asthma see this review by
my supervisor. To see the abstract of an oral presentation presented at
The British Occupational Hygiene Conference during the spring of 1996
Workers who develop occupational asthma may improve if removed from exposure however in some cases symptoms may persist for years after exposure ceases. Some form of long term drug therapy may be required. The avoidance of re-exposure to the relevant chemical should promote a favourable outcome.
It is in the interest of both employer and employee to provide and comply with measures to prevent occupational disease and injury. Prevention of occupational asthma involves two steps:
The first step is not easy for either employer or employee - until very recently the only way of knowing whether a chemical causes occupational asthma is if it has been reported to. This would require extensive searching of medical literature (in a number of languages).
- Identification of hazardous chemicals.
- Elimination, substitution, reduction and/or containment of the hazardous chemicals.
The second step, whilst not trivial, is within the power of employer and employee. Care must be taken not to replace one hazardous chemical with another of equal or greater hazard.
Which Chemicals are Hazardous?
Whilst it is not possible to produce a 100% accurate list of chemicals that pose and occupational asthma hazard risk it is possible to indicate some of those asthma causing compounds that have been identified as a problem. You can also find a general overview of the types of chemicals with regards occupational asthma.
- Ross, D.J., Sallie, B.A. and McDonald, J.C. (1995) Occupational
Medicine 45, 175-178.
- Chan-Yeung, M. and Malo, J.L. (1995) New England Journal Of
Medicine 333/2, 107-112