Reply #166: I'll post this again in case anyone is interested. Pool filter cleaners contain 2-butoxyethanol.

[LTX]

Here's a common one:

http://www.h2opoolproducts.com/product_info.php?products_id=1149

And here's the Material Safety Data Sheet on the product, listing 2-butoxyethanol:

http://www.poolwater.com/msds/all/Leisure%20Time%20Instant%20Cartridge%20Clean.pdf

And here's a quote from the article linked in the o/p:

The Scheblers found Robert Naman, a Mobile, Alabama chemist who’s performed multiple tests (1, 2, 3) for WKRG Channel 5, also out of Mobile.

“Warren collected a water sample from the pool filter on August 17th… packed the sample according to Mr. Naman’s instructions, and overnighted it to his Mobile, Ala. lab that same day,” she noted.

I think we have a smoking gun.