Have you ever smelled a lake turning over? Or the water coming from it? Sounds something like what you're describing, with a faint "fishey" smell added.
There's a slight chemical tinge to it, not sulfurous. Might be something like the smell you describe, though.
Whereever it's coming from and whatever it is, it's not from Texas, that's for sure.
Ungh. I've smelled (and seen) a lake turning over. It's gross.