A fluid catalyst cracking unit (FCCU) is often one of the key process units in many refineries. It can also be a major source of atmospheric emissions. As refiners all over the world look to lower emissions, some are taking actions to decrease FCCU flue gas emissions. As part of a recent FCCU revamp, Enap Refinerias S.A. (ENAP) commissioned a wet scrubber to control FCCU flue gas emissions at the Bio Bio Refinery in Hualpen, Chile. The revamped FCCU and new scrubber were successfully commissioned in August 2019. This was ENAP’s first experience using a wet scrubber with an FCCU. It is also the first scrubber operating on an FCCU in South America. ENAP’s strategic plan also includes the installation of a second wet scrubber on the FCCU at the Aconcagua Refinery in Concon, Chile, which is currently in the execution phase. This paper discusses how these major emissions control projects evolved, how and why technologies we selected, and emissions control results