also non-dysbaric disorders associated with diving, which include the effects of the aquatic environment, such as drowning, which also are common to other water users, and disorders caused by the equipment or associated factors, such as carbon dioxide and carbon monoxide poisoning. General environmental conditions can lead to another group of disorders, which include hypothermia and motion sickness, injuries by marine and aquatic organisms, contaminated waters, man-made hazards, and ergonomic problems with equipment and tasks. Finally there are pre-existing medical and psychological conditions which increase the risk of being affected by a diving disorder, which may be aggravated by adverse side effects of medications and other drug use. Treatment depends on the specific disorder, but often includes oxygen therapy, which is standard first aid for most diving accidents, and is hardly ever contra-indicated for a person medically fit to dive, and hyperbaric therapy is the definitive treatment for decompression sickness. Screening for medical fitness to dive can reduce some of the risk for some of the disorders. Risk The labels used to classify dives are not sufficiently precise for analysing risk. Terms like "recreational", "technical", "commercial", "military", "scientific" and "professional" are used but are not precisely defined, particularly for risk analysis as they do not identify specific contributors to diving risk. Categorisation by depth and obligation for decompression stops is also insufficient to classify risk. The diving mode has a large influence on risk, and choice of diving mode is commonly based on the outcome of a risk assessment for the diving operation. Risk management Risk management has three major aspects besides equipment and training: Risk assessment, emergency management and insurance cover. The risk assessment for a dive is primarily a planning activity, and may range in formality from a part of the pre-dive buddy check for recreational divers, to a safety file with professional risk assessment and detailed emergency plans for professional diving projects. Some form of pre-dive briefing is customary with organised recreational dives, and this generally includes a recitation by the divemaster of the known and predicted hazards, the risk associated with the significant ones, and the procedures to be followed in case of the reasonably foreseeable emergencies associated with them. Insurance cover for diving accidents may not be included in standard policies. There are a few organisations which focus specifically on diver safety and insurance cover, such as the international Divers Alert Network Risk assessment is