Carbon Monoxide

Carbon monoxide is predominantly man-produced and results from incomplete combustion of hydrocarbon fuels. It is highly poisonous, odorless and tasteless, making it difficult to detect in isolation. Fortunately, it commonly occurs with other compounds, which is why divers are advised to avoid diving with air that has a taste or smell. Although carbon monoxide contamination is rare in diving air, it can happen, usually due to compressors that are either improperly placed (resulting in pumping exhaust gases into the dive cylinder) or lubricated with inappropriate substances that partially combust and form carbon monoxide during the heat of compression.