You could be on the hook for the cost of environmental cleanup.You need legal representation from an attorney with experience in gas stations.

@Jack Tucker - A few things about gas stations that you need to keep in mindLenders will require that a Phase 1 and\or 2 be performed to ensure there are no environmental issues.  

I'd also do a LBP self test and maybe even a phase I environmental depending on the building.

You won't be able to get a permit and if you don't have a permit you are going to get cited and lose in the environmental "court"

You will need a Phase I Environmental Assessment.

Some of the conditions they want me to waive are: Phase 1 & 2 environmental study, they cant provide me with current tenant leases, can't provide building plans, surveys, fire certificate, previous building expenses.

Closing costs, environmental reports, carrying costs are going to be free too?  

He is also going to be budget conscious.  

We backed out of the deal due to environmental concerns regarding contaminated soil from a UST that was taken out back in 1987.

I got my start by buying my personal residence and when we wanted to move made a conscious decision to keep it.