Accident (in the gas industry) is a breakdown or damage of any mechanism during operation. In the gas industry it can be partial or full destruction of facilities and/or devices, uncontrolled discharge (and/or explosion) of hazardous chemicals which can cause a dangerous impact on personnel, population and environment. A breakdown of an engineering device sets it to a failure condition; however, it may retain (in some cases) capability to work.

Gas industry accidents, which have the most dangerous consequences, include:

• well blowout in the process of drilling and/or gas production;
• full or partial break (ruptures, cracks) of high pressure pipelines (underground, overhead, submerged);
• oil or gas condensate spills on the water surface.

The most serious consequences of emergency gas discharges cause:

• thermal radiation in case of its inflammation;
• shockwave impact in case of atmospheric explosion;
• toxic impact on people and environment.