smelly pants, what are they feeding you?

I have a weird question. Does anybody else ever put on a pair of cords and notice a weird, chemical-y, almost oily smell on them? I swear, I washed these pants before I wore them today, but when I think about it, I have a couple other pairs of cords that give off this same scent. They're mainly cotton, right? So what is this odor? Now I'm all creeped out by my pants! Ack!