Abstract
Three groups of 18 rats were exposed respectively to very large doses of o-chlorobenzylidene malononitrile (CS) of 90 000, 60 000 and 30 000 mg min per m3 and then sacrificed at intervals from 15 min to 2 days, after which lungs were examined macroscopically, by electron microscopy and conventional histology.
Distress appeared to be maximal between 18–36 hr after exposure, when a total of 6 deaths occurred; 4 after a dosage of 90 000 mg min per m3 and 2 after a dosage of 60 000 mg min per m3. In animals that died there was severe congestion and areas of alveolar haemorrhage, with some interstitial oedema. Survivors showed less marked pulmonary congestion, haemorrhage and oedema. Electron micrographs revealed changes to the alveolar epithelium and interstitium in the form of accumulation of fluid between the membrane layers and collagen-containing areas of the septum. The presence of fluid was associated with degenerative changes of the epithelium and endothelium leading to rupture or dissolution of the capillary wall, so allowing the extravasation of red blood cells and fluid into the alveolar space.
This study showed that death after exposure to very high concentrations of CS grenade smoke is accompanied by congestion and severe capillary damage giving rise to pulmonary oedema and haemorrhage. Lung appearances of animals which survived the period of maximum distress suggest that the induced damage is transient. Only if the smoke was used in confined spaces or was deployed in wildly unreasonable concentrations, where persons involved were unable to escape, would the conditions of this investigation even begin to be approached.
Get full access to this article
View all access options for this article.