Occupational asthma and the chemical properties of low molecular weight organic substances.

Various low molecular weight substances cause occupational asthma, and there is scope for studying their chemical properties in relation to their propensity to cause this condition. Twenty-nine organic substances (molecular weight < 250), with or without oxygen or nitrogen atoms, were compared to control hazardous substances obtained from the list of occupational exposure limits. There were significantly more reactive groups in the active chemicals than in the controls. Carbon to nitrogen double bonds were also significantly over-represented in the active chemicals. If confirmed in a fuller study, these data could yield useful information on the causation of occupational asthma and on the hazard assessment of novel chemical entities.