In situ burning is an oil spill response tool that involves controlled ignition and burning of an oil spill on the surface of the water or in a marsh. When used early in a spill before the oil weathers and releases its volatile components, burning can remove oil from the waters surface very efficiently and at very high rates. Removal efficiencies for thick slicks can exceed 95 percent. In situ burning offers a logistically simple, rapid, inexpensive and if controlled a relatively safe means for reducing the environmental impacts of a spill. Burning gasifies the oil during combustion and rapidly changes large quantities of oil into its primary combustion products (water and carbon dioxide). This greatly reduces the need for collection, storage, transport, treatment and disposal of recovered material. Burning requires minimal equipment although some specialized equipment (fire resistant boom and igniters) and training is required. The use of towed fire containment boom to capture, thicken and isolate a portion of the spill, followed by ignition, is far less complex than the operations involved in mechanical recovery.

There is a limited window of opportunity (or time period of effectiveness) to conduct successful burn operations. The type of oil, prevailing meteorological and oceanographic conditions and the time it takes for the oil to emulsify define the window. Once spilled, oil begins to form emulsions. When water content exceeds 25% most slicks are unignitable. In situ burning is being viewed with interest as a response tool in high latitude waters where other response techniques may not be possible or advisable due to the physical environment (extremely low temperatures, ice-infested waters), or the remoteness of the impacted area. Additionally, the magnitude of the spill may quickly overwhelm the deployed mechanical equipment necessitating the consideration of other techniques in the overall response strategy.

The Minerals Management Service in situ burn program consists of research and development projects (many conducted jointly with international partners) to evaluate various aspects of burning as an oil spill countermeasure. Emphasis is on the emissions to air and water, burn equipment evaluations, smoke plume modeling, and research to extend the "Window of Opportunity" through the use of chemical emulsion breakers.