No Deborah,  You are not old!!! I'm Old!!!!!  I will tell you what I know regarding environmental liens.  Back in the early to mid 80's(see I told you I was old)  The State & Federal Government Environmental Agencies were authorized to attach liens to properties that had been found to be an environmental hazard.  The liens were to insure the cleanup of these properties (brown fields, old gas stations, some farm properties etc).  When the cleanup was done, inspected & deemed not a hazard anymore the lien was to be released. 
The problem is that when the liens started appearing in the Court Houses, no one could decide where they should be filed.  To my knowledge most got filed in miscellaneous indexes.  In some cases they were filed in the Clerk of Courts/Common Pleas (like a Judgment Lien),  also deed indexes.  Actually there were several filed back in the 80's. 
Recently there has been renewed interest in environmental problems.  The properties are usually commercial.
My advise is to ASK your counties & if there are some more seasoned veterans around ask them, where would they file an environmental lien.  If they weren't around in the 80's they probably won't know what an environmental lien is.  So I would search every index I could think of.  There are probably not that many liens.  But you don't want to miss one!!! 
Hope this helps.

Wanda Steudel
AccuSearch Co