Definicija: 1) Flares use open flames during normal and/or emergency operations to combust hazardous gaseous. The system has no special features to control temperature or time of combustion; however, supplemental fuel may be required to sustain the combustion. Historically, flares have been used to dispose of waste gases in the oil and gas industry and at wastewater treatment plants having anaerobic digestors. Regulation for thermal destruction of hazardous wastes limit the practical use of flaring to combustion of relatively simple hydrocarbons, such as methane from digesters or landfill gas collection systems. 2) A control device that burns hazardous materials to prevent their release into the environment; may operate continuously or intermittently, usually on top a stack.

Definicija: 1. Pri sežigu se uporablja ogenj za normalno in/ali izredno zgorevanje nevarnih plinov. Sistem nima posebnih naprav za kontrolo temperature ali trajanja zgorevanja; čeprav je za zgorevanje morda potrebno dodatno gorivo. V preteklosti se je sežig uporabljal za uničevanje odpadnih plinov v naftni in plinski industriji ter v čistilnih napravah za odpadno vodo, ki so uporabljale postopek anaerobnega razkroja. Predpisi o sežigu nevarnih odpadkov omejujejo sežig teh odpadkov na relativno preproste ogljikovodike, npr. metan, ki nastane v čistilnih napravah ali se kopiči na deponijah odpadkov. 2. Kontrolna naprava, ki sežiga nevarne snovi, da se prepreči njihov izpust v okolje; lahko deluje neprestano ali občasno, ponavadi se nahaja na vrhu dimnika.