Propane residence / Vapor Pan

We have owned this home since April 2012. It passed all inspection per the inspector of record. We are selling this home July - Aug 2018. We are in escrow. The said inspector has noted that we need a vapor pan in attic . Every Air . Heating company says the door to attic is too small to enter for this so called vapor pan. Alternative to break open the ceiling and reconstruct the drywall to accommodate this request. If we purchased this home in 2012 knowing we are serviced by propane , why aren’t we grandfathered in to approve this escrow? please respond.

do you mean emergency drain pan ?