The International Journal of Emergency Medicine describes carbon dioxide (C02) as a product of combustion, fermentation and respiration. It is a colorless, odorless and non-flammable gas that accumulates near the ground as it is 1.5 times heavier than air. Enclosed spaces are vulnerable to C02 buildup as it displaces the oxygen in the air. The journal article used the term "confined space hypoxic syndrome" to describe confined space accidents that have occurred in water meter pits, tanks, holds of ships, mines or underground storage bins due to oxygen-deficient atmospheres. Carbon dioxide causes asphyxiation by hypoxia (oxygen deprivation) and it is also a toxicant that can cause unconsciousness and respiratory arrest within one minute. Carbon dioxide poisoning can also occur when there is inadequate ventilation for scuba divers (this condition is also called decompression sickness). E-Medicine Health reports the following carbon dioxide poisoning symptoms: Nausea Vomiting Dizziness Headache Rapid breathing and heart rate Flushing Severe cases of carbon dioxide poisoning can cause confusion, convulsions and loss of consciousness.