My husband came home from the laundromat with a huge bag of our laundry (wet) that just reeked of some laundry detergent (Gain super scented maybe?) with an undernote of some caustic chemical. My eyes literally started watering when he opened the bag. He felt so awful and took it back to the laundromat and rewashed it all with febreeze but it was still awful. It's been hanging on the line for over a week and it still stinks of mock floral and something worse under (pesticide maybe - it smells deadly) I have ordered a product called Enviroklean and am going to try it, but friends tell me that if there is any poly or spandex in the clothing that nothing will remove the smell. Has anyone else ever dealt with this? Should I just take the clothes to the dump?
rewashed it all with Febreeze
That will of course add its own odor to the mix, compounding the problem.
Make sure that whatever you wash it with is labelled as unscented (e.g. Tide Free).
You didn't mention trying Borax, which is noted for its ability to absorb odors.
(People have been using it for centuries when washing diapers.)
Borax is one of the first products I'd try.
Make sure to use pure borax, and not simply some product that contains borax.
(E.g. Tackle Funky Odors | Twenty Mule Team Borax.)
I also do not like leftover detergent in my clothes. Although time and energy consuming, I wash the clothes the second time, without detergent - practically a serious additional rinsing cycle.
If the water you use is hard, then installing a hardness remover will help you get cleaner clothes in the end. However, if you can only do your laundry at the laundromat, you are mostly out of option from this POV.