This map documents some of the largest drilling accident related methane releases into the atmosphere. These “invisible spills” are in addition to the millions of wells worldwide that can release up to 20% of their methane (and other gases) as fugitive emissions.
Fugitive emissions are emissions of gases or vapors from pressurized equipment due to leaks and other unintended or irregular releases of gases, mostly from industrial activities. As well as the economic cost of lost commodities, fugitive emissions contribute to air pollution and climate change. A detailed inventory of greenhouse gas emissions from upstream oil and gas activities in Canada for the year 2000 estimated that fugitive equipment leaks had a global warming potential equivalent to the release of 17 million metric tonnes of carbon dioxide, or 12 per cent of all greenhouse gases emitted by the sector. Venting of natural gas, flaring, accidental releases and storage losses accounted for an additional 38 per cent.
Fugitive emissions present other risks and hazards. Emissions of volatile organic compounds such as benzene from oil refineries and chemical plants pose a long term health risk to workers and local communities. In situations where large amounts of flammable liquids and gases are contained under pressure, leaks also increase the risk of fire and explosion.
Leaks from pressurized process equipment generally occur through valves, pipe connections, mechanical seals, or related equipment. Fugitive emissions also occur at evaporative sources such as waste water treatment ponds and storage tanks. Because of the huge number of potential leak sources at large industrial facilities and the difficulties in detecting and repairing some leaks, fugitive emissions can be a significant proportion of total emissions. Though the quantities of leaked gases may be small, gases that have serious health or environmental impacts can cause a significant problem.