I changed my mind and went out today and retrieved all of the dumped bags I found recently in the fire lane as well as some other material that had been dumped earlier.
The bags appear to contain some old blue tarps, perhaps dumped by a roofing contractor.
This section of the fire lane opposite an empty lot remains the main problem. I also found a tire that was freshly dumped. I put it against the fence in a less visible section. I'll have to wait for an opportunity to dispose of it for free.
In an unrelated note, this has been a good season for sandspurs. I need to clear the main entry path in case I get hikers from Trek Ten or someone else.