The info below comes from this site: https://www.proactiver-fn.com/index.php?content=faq§ion=flaring
“Flaring” is the burning off of unwanted gas to keep the pressure within the well at a safe level. It is a great source of Greenhouse gas pollutants.
Well Test Flaring
“Well test flaring occurs during drilling and testing of all oil and gas wells. This is a standard practice used to determine the types of fluids the well can produce, the pressure and flow rates of fluids and other characteristics of the underground reservoir. If there are pipelines nearby, operators may be able to direct the test gas to a processing plant and this process is called “in-line testing”. This is not a practice that is feasible for some exploratory wells as there may not be any pipelines and processing plants nearby. The pressure, flow and composition of the gas has to be determined before it can be safely handled by the pipelines and processing plants. This information determines the economic value of the well and what type of production facilities will be installed. Also, additional flaring during “under balanced drilling” operations is performed to dispose of the gas that comes to the surface. This process speeds up drilling and reduces the damage to producing formations by the drilling fluids. Some well test flaring may be necessary after certain well servicing operations. The average flaring duration is 2.5 days.”
And this is what I found about what the burning is releasing.
What is Emitted from the Flares?
“It has been assumed that flares burn at 99% efficiency. However,1% of incomplete combustion can produce Carbon Monoxide (CO), unburned hydrocarbons, particulate matter (soot and ash), volatile organic compounds (Benzene, Toluene, Xylene), other organic compounds known as Polycyclic aromatic hydrocarbons and small quantities of Sulphur compounds such as Carbon Disulphide (SO2) and Carbonyl Sulphide (COS). Benzene is known as a cancer causing compound and Carbon Disulphide is also classified as a poison affecting the central nervous system. The effects of these depend on the magnitude, duration and frequency of exposure. Many of these compounds are not unique to flaring and are common products of incomplete combustion in emissions from automobiles, forest fires, stubble burning, barbecues and cigarettes.”