I have that problem myself sometimes but not always. It seems to be ok sometimes when I go and then the next time I have no problems at all and it's the same shop. Either they are spraying something or they get a new batch of fabrics in, is when I have the most problems. Usually I throw all the fabrics in the truck of the car and when I get home they go straight to the washing machine. I only wash them once but I do use 1 cup of vinegar in the water and that seems to do the trick for me. I have had one piece of fabrics that I could not get a smell out of and it wasn't that noticeable until I put it in the dryer. I ended up throwing the fabric out because I would not want someone sleeping with that order. It' smelled like burnt oil or something. Like I said I didn't notice it until after I had dried it.
Another thing you must think about is that most fabric is now made overseas and it is shipped here so anything they spray in the ships to prevent mice and other insects is also possibly in the fabrics since they absorb orders. I know they wrap the fabric but still you never know the conditions in which it was shipped.