Ask them if they're okay with the smell of the orange natural cleaner (odds are these guys will also be afraid of chemicals). 

We were successful with a new chemical treatment. 

Things like old ovens, random chemical waste, excess trash left behind by a tenant, etc.I used to drive a sedan and I was able to make that work, but having a truck is just a bit easier, in my opinion.

We hired a pest company that used a new chemical treatment at the time, which would have been about 2013. 

The prognosis from the cleaning crew was that the chemicals they would need to use to clean it, probably wouldn't make it very safe as a fridge for food afterwards.

Born and raised in AZ, I completed my Masters in Chemical Engineering this past May, 2015.  

Talmar is now Chemical Bank.

Much like the FDA will allow additives and chemicals void of nutrition in your food.

For example, I would not generally take a lien on a old chemical storage site. 

Clearly my summary is very simple, and there are a lot of areas you can get tripped up on in retail, i.e. did the center you are buying have a dry cleaner in it 40 years ago that dumped their chemicals down the floor drain?