If you look at the inside of the bladder and it has a "slick" appearance, you might try adding a hot water and dish soap through the system. Thermoplastics like Polyurethane,Polyethylene and Ethylene Co-polymers (like EVA) can sometimes have an oily residue left behind following the molding process. You could also try a solution of either heavily salted water, or baking soda and water through the system. I haven't used a Badlands hydration bladder, but have used Camelbak and Platypus systems (prefer platypus, except in really cold situations), and haven't had to deal with the "plastic" taste; although I am pretty sure when I bought them they both said to wash and rinse thoroughly before use. Good luck; I hate that chemical taste. It would be a bummer if you have to ditch the bladder just to spend more cash on a new one.