Carbon monoxide poisoning: a potential hazard to speleologists?

Many speleologists habitually employ acetylene lamps as an aid to cave exploration. Acetylene generated from calcium carbide bums incompletely in acetylene lamps, and production of carbon monoxide appears likely. In order to establish the potential hazard of carbon monoxide poisoning during speleological activities, an experiment was carried out during a rescue training exercise of the National Speleologic Rescue Service of Lombardy, Italy. Fifteen voluntary rescue technicians provided venous blood samples before and after 14 hours of caving, in enclosed spaces with poor air circulation. The data show a clear and statistically significant decrease of blood carboxy-haemoglobin, probably due to the effects of hyperventilation in surroundings that are effectively free of carbon monoxide.