Oxy-Fill

Oxy-Fill is a business in Rapture that specializes in refueling the Drills used by the Big Daddies. They are the manufacturers of the Fuel Stations seen throughout the city.

BioShock 2
Outside the research laboratories of Fontaine Futuristics is a false Oxy-Fill station that conceals the way into Persephone. After Subject Delta obtains the genetic key from Gil Alexander, he gains acces to the elevator leading down to Persephone.