Phil Cassidy own his own boomshine wearhouse in Little Havana. Phil asks Victor Vance to drive him to his wearhouse because of a threat attack by the Cholos. When they arrive, one of the wearhouse doors was open. When Phil opened the door more he was blown back by an explosion. Because of this, Phil now knows that if the liquid was ever to be heated up, the liquid will create a massive explosion. Victor decides to save the liquid by using a forklift to prevent explosion and the loss of Phil's boomshine. The liquid would later be used by him and Victor to protect themselves for Jerry Martinez' goons.
In the events of Grand Theft Auto: Vice City, Phil hires Tommy Vercetti after pulling of the bank job. When Vercetti arrives for his first job, he notices that Phil is testing his boomshine bombs in his area. Later on Vercetti returns but sees a drunk Phil Cassidy testing his new detonating boomshine bombs. Attempting to set them off, Phil mentions that the batteries are dead and the new ones are sitting next to the bombs. Phil puts the new boms in the detonator and the bombs go off next to Phil, which causes him to blow off his right arm. A drunk Tommy decides to drive Phil in his Patriot to a military hospital in Little Havana.
In GTA III, Boomshine is known to still being produced illegaly in Liberty City. The drink was known to have driven the homeless community insane.