[tubercle]

...i am less worried about the chemicals leaching than i am about oxidation. 

 I would be more worried about chemicals that oxygen. The fermentation process is only going to last a few weeks and then it is going in to bottles and/or kegs.

 Oxygen molecules traveling through plastic is probably measured in molecules per year.

 The alcohol in the beer acting as a solvent is more likely to leach out death. You will get more oxygen in the beer by transferring to a container than through the walls of the plastic.

  Use only HDPE.

  This is science as Tubercle understands it.