In cases of environmental contamination, that can limit what could be there in the future, for example a former car repair shop (that you found the stale yelp reviews for) is likely sufficiently contaminated that it can only ever be something like that, you won't be able to put a daycare center or restaurant in there. 

These people honestly dont care about you and you shouldn't let what they say contaminate your business reasoning.

You can rent machines that put out near lethal doses of ozone that use a timer that you set, vacate and then come back hours after the ozone disperses.We've used ozone to get rid of bed bugs, mold, smoke damage, cigarette & weed odors, etc.Recommend you Google how to get rid of meth contamination, so you understand the process and don't get ripped off!

My attorney told me that this maybe a huge proplem.If there is some contamination come from the trash and if the neighbors use well water,it will take forever to get permit from the environment department. 3) I need find out if the deed is subdividable.If the deed says this lot is not subdividable,it's no possible to develop this land. ........

Even outside the main contamination zone, they are still taking temperatures of employees when they enter buildings to go to work.

What not to like about PEX, taken from page 6 of next link:"Do not spray on or allow organic (petroleum-based) chemicals, petroleum distillates, termiticides or pesticides to come into contact with PEX pipes, otherwise permeation of harmful chemicals may occur through the pipe wall and contaminate drinking water."

Rima and I keep people out of trouble with the highly-regulated toxic and hazardous materials - asbestos, lead, VOCs, soil and groundwater contamination, plus indoor air quality and the almost unregulated mold.