A pressure vessel may include a body formed of a polymeric material. The body may extend between a first end and a second end. The body may include a center column defining a first inner volume extending between the first end and the second end. A wall may be connected to the center column. The wall may surround the center column and define a second inner volume therebetween. The second inner volume may be disposed annularly around, and fluidly separate from, the first inner volume. The pressure vessel may also include a first end cap coupled to the center column at the first end and second end cap coupled to the center column at the second end. The first end cap may close off the first inner volume at the first end. The second end cap may close off the first inner volume at the second end.