@Bret Allen We provide the house pest-free and will re-treat if reported in the first 30 days.Our lease has had the term "any additional or periodic pest control is the responsibility of the tenant" for at least the 11 years I've been here, and it has been vetted by our attorney.I understand your opinion may differ, but I would rather have a tenant raise the issue of being responsible for their own cockroach problem (we do SFH, so neighbors don't play in) than being named in a suit for damages because somebody had a fatal reaction to our pest control vendor's choice of chemicals. 

Harsh but true.

What about household chemicals which are considered toxic or flammable , will these be considered a breach of lease?

Not to sound harsh but if he truly is "going to die soon" perhaps it is better that you do nothing it terms of "getting rid of them" now. 

Everybody does, it's part of life.I certainly respect that you can and should run your properties however you see fit, however it's a bit harsh to speak in absolutes when saying if they've gotten one DUI, they will continue to drink and drive.

The enzyme products work chemically to change the urine into something that is harmless and does not smell bad.  

Forget the 15k and treat it as money well spent for the gift they gave you--your life.I'm sorry for being harsh.

I personally don't use a lot of chemicals around my children & would hate for a tenant's family to be adversely affected by my pest control.

If this happens, then at least you will learn what NOT to buy in the future.One more bit of advise, and be warned this may sound harsh but I say it because I think it is what you need to hear: stop blindly believing and following everything you read or hear on BP (or anywhere else).

Certain chemicals can make the water unpotable.