The seller is removing underground oil tank and remediating the soil contamination.

You may be better off removing sections of wall and / or ceiling that have been contaminated.

A Phase I ESA (typically the first step) usually costs a couple thousand dollars, and the cost could go WAY higher if they find any contamination on the property and cleanup is required. 

Be careful of hanging out those who share advice and have no assets or experience to back it up, they will quickly contaminate your goals (quicksand syndrome I call it). 

Military facilities are notorious for being contaminated with various chemicals. 

The link you provided states that AZ law prohibits anyone except the landlord, property owner or manager from entering the suspected meth lab until it has been remediated by a state-approved remediation firm.When I called a local remediation firm about a meth property I was interested in buying, he said that any meth contamination in a home automatically labels the home as a lab.

If there are any findings of contamination, proceed with extreme caution or you could find yourself on the hook for a very expensive cleanup.Also investigate the age of the underground tanks and what the state requirements are. 

Frank It is a sewer back up, which means the drywall is contaminated with fecal matter, so the only option is removing it.

Neither property is listed on the EPA or Mass DEP lists of contaminated properties, so I am wondering what database the bank looked at which spurred the additional inquiry.

Neither property is listed on the EPA or Mass DEP lists of contaminated properties, so I am wondering what database the bank looked at which spurred the additional inquiry.