Seeing that it was a dealership, I am assuming a car dealer here, but regardless you may have an environmental issue on your hands. 

The remediation company will not give an absolute move out recommendation, because they refer to a third party company for environmental assessment (minimum 300-1200 not covered by insurance), but the tech has indicated it would be a good idea for them to move out for 5-7 days.  

Such are not marketable.Contaminated properties are high on the list to stay away from, environmental issues can be very expensive to clean up. 

You would obviously have to factor in demo costs of existing structure, any environmental abatement etc, however that would be my first approach on establishing quick value.  

It could be something wrong like drug activity, new company air pollution and etc. 

See below, the contract reads  "  ... by one or more licensed or certified inspection services: home, radon, environmental, lead-base paint, lead-based paint hazard or wood-destroying insect infestation." 

Department of Treasury with usc exceptionState Tax LienLien by USA or Dept of JusticeUS Department of StateOther Federal AgenciesFrequent Superior Foreclosure-Liens:Code Enforcement for debris removal or mowingDemolition or Environmental Based Liens State child support lienBoard of County Commissioners for special assessmentsUtility LiensWater/Sewer Delinquency (only in selected states)County (and/or School/Township) for unpaid taxesCity for road improvements, maintenanceHere are some of the judgment and liens that will be wiped off from the property (not the borrower who lost the title) if the lien holders were properly notified and "had the right to bid on the property at the auction":2nd and junior position mortgages, such as home equity loans, etc...Credit Card Judgments recorded after the foreclosing mortgage Personal Judgments recorded after the foreclosing mortgageMechanic's Liens recorded after the foreclosing mortgageOther Judgments outside of the ones listed above  

@Andy K  Here is a very good reference from the Environmental Protection Agency.  

If not, here is a link to the Landlord reporting form: http://www.maine.gov/dhhs/mecdc/environmental-health/rad/radon/documents/LANDLORDS%20REPORTING%20FORM%20FOR%20RENTAL%20TESTING.pdf which you will need to complete and return to DHHS Radon department.

Restrictions on what can be built,minerals rights,environmental hazards,flood prone,etc.