Almost 400 substances have been identified as possible asthma agents - many of them are found in workplaces. 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.
- Some hardwood 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.
- Laboratory animals excreta/secreta.
But over 200 substances have been identified as possible asthma agents. In addition to the above, the Health and Safety Executive (UK's VWA) has identified these as respiratory sensitisers (a cause of asthma) and determined that they should be labelled with R42: 'May cause sensitisation by inhalation':
Another list of Low Molecular Weight Chemicals causing Occupational Asthma has been published by University of Edinburgh. The University advised that the basic criterion for a chemical to be included in the list was that the diagnosing physician attributed the occupational asthma to the stated compound. However, it strongly advised against drawing conclusions from the list alone. It recommended doing a thorough literature review be done and seeking advice from suitably qualified physicians.
When inhaled over a period of time:
- Fact sheet (available in many different languages) from the European Agency for Safety and Health at Work: Respiratory sensitisers
- On isocyanates:
Last amended May 2020