I don’t know about these products with regard to BPAs or other harmful chemicals. But I can tell you they’re dangerous if you’re stupid and you use them wrong.
Camelback tells you to put only water in their bladders. Do not ignore this instruction. Do not put in Gatorade or any other sugary fluid.
If you choose to sip Gatorade from it, be absolutely sure to clean the bladder very thoroughly after your ride, and then let it dry out.
Whatever you do, never set it down in your hotel room with traces of Gatorade remaining, forget it for about about a week, then fill it with water and go on another ride, drinking the moldy residue along the way.
Don’t ask me how I know. Just trust that this will make you sick.