An apparatus coupled to a chamber for processing extreme ultraviolet radiation includes a gas inlet configured to direct exhaust gases from the chamber into a combustion zone. The combustion zone is configured to flamelessly ignite the exhaust gases. An air inlet is configured to direct a mixture of air and a fuel into the combustion zone. A control valve is configured to change a volume of fluid exhausted from the combustion zone. A controller configured to control the control valve so as to prevent a pressure inside the combustion zone from exceeding a preset pressure value is provided.