But, there is a question about whether "environmental contaminants" have ever been used in the house.

Then, you'll take the scope of work to a remediation company who will do the actual work (tearing out the mold contaminated materials).  

If this were a contaminated commercial property, think -$50k (yes negative - seller paid buyer $50k to take it off his hands). 

Gas Station owners pm me if you don't want to post.What I have found conclusively is that with gasoline you are lucky to break even and then the real income comes from the convenience store purchases.Looking out for contamination is a big thing.Any other ideas for owner/operators.Thanks in advance.

For example, if an ESA is done and it finds substantial environmental contamination on the grounds, then it might not make sense to do the deal.

I'm quite sure the AC system will also be full of contaminants from the smoke.

All of these may not be triggers for you and me but it may be triggers for other investors.The strategy you had in place is not working -triggerThere were additional costs that the previous owner did not reveal to you -triggerIf you got ripped off by people -triggerIf you partnered with someone and you do not get along or can't agree on nothing - triggerOne of the big employers in the area filed bankruptcy -triggerOne of the big employers in the area decides to move to another city or state -triggerhome owners association is similar to Hitler's gestapo -triggertenants association is unreasonable and troublesomeIf you see another deal that you like better -triggeryou feel the market is going to change -triggerIf the weather changes and suddenly you find that your area is not the same ie drought or flood or mud slide -trigger Insurance increases because of weather change -triggerfound out that the land is contaminated - triggeryou are tired of dealing with the property -triggertenants not paying rent -triggeryou took on more than you can handle -triggerproperty taxes went up -triggergangs in the neighborhood -triggerfamily issues change your priority and you simply cant handle it no more -triggeryour tax abatement has expired - triggertransportation has discontinued in the area -triggerlegislation to put in a new transportation station has been vetoed or approved -triggerthe team (ex contractors, project managers, etc) you tried to put together doesn't work out- triggerillegal activity found on the premises -triggertenants tell you place is haunted and you know someone died on property -triggerdemonic neighborsabundance of pests -triggersink hole formed - triggercess pool discovered -triggerwater contaminationpopulation changeschools accredation changesschools shut downtenants or their family starts shooting at each other or youwrong type of business sets up shop near your property, or they are too close or your comfort. ie gas station or drug dealer or prostitution or cemetery or factorywhatever does not float your boat -trigger

Some areas have really bad contamination.

We spent $125K on the purchase, $75K to complete units, paint the house, build a front porch (not pictured), and another $16K on demolition of the rear (asbestos contamination sucks).

@Joshua Carter a SIGNIFICANT portion of my due diligence and inspection process requires the utilities to be on.For instance, I run all plumbing extensively to check for leaks, I ensure that appliances are functioning correctly, I check all lights and electrical outlets for functionality & ground, we check the fuse boxes for functionality & condition, we assess the performance of furnace & AC systems, and water heaters, we check the functionality & safety of the gas lines, scope the sewer main and assess water flow, test for radon & meth contamination, and basically give the entire property a thorough "test drive"  --which isn't possible if the utilities are off.