I took a chance and bought these leggings in black and brown and found that the smell was overpowering.  I tried washing by themselves and airing them out for over a month and it that cut the smell down (or I've just gotten used to it.)  I wore the leggings and didn't seem to have an issue while I was out and about so I didn't think twice about tossing them in the wash with the rest of my clothes.  Huge mistake.  The leggings made all of my clothes reek to the point that I thought they were ruined.  I ran my wash with baking soda and and had it on a soak setting.  When that was through, I washed my clothes again and added vinegar to the rinse cycle.  This technique saved my clothes.  I plan to try the same washing method on the leggings alone and I really hope it works.