Seems to be some strong feelings here about whether to blame the FBOs exclusively or the EPA, or the NTSB. Let’s look at some points. The NTSB ONLY investigates and advises, period. They legislate nothing. The EPA is only interested in environmental issues, they do not get into various parts of industry and how they conduct things. Okay, with the NTSB and the EPA “out”, that leaves the FAA and the various FBOs. A bureaucracy the size of the FAA is pretty ponderous but theoretically require that DEF and other additives be labeled / stored carefully separated from each other. That might help some. FBOs, well it kind of comes down to them, the end user here. First, their equipment might be exempt (I am not an expert here) from the DEF requirements due to not be on road machinery. They, as a group, might be able to get a waiver if they are not blanket exempt. I am sure that none of them, however, want DEF or anything else in their fuel supplies. I am reasonably sure that the vast majority of them train, emphasize, and stress proper servicing of their vehicles.
The human factor is the critical point here. No matter how much anyone in the “chain” stresses the issue, human error WILL OCCUR and DEF will end up where it doesn’t belong. PERIOD. I worked for a company with a huge fleet of vehicles. That company stressed very strongly the proper servicing of those vehicles with fuel, DEF, and other additives. In spite of that stressing, diesel ended up in gas tanks, gas in diesel tanks, DEF in places you wouldn’t believe, ditto with coolant. The human factor.
So, where does this leave us? The FAA, the EPA, the FBO industry, and end-user groups should work together to “stupid-proof” the end process to the max extent possible. How, you ask? How about giving thought to using CNG fueled vehicles only around airports? How about using battery powered vehicles where feasible? How about extremely unique fittings for various refill actions? While these are only suggestions, they are offered with the hope of eliminating the human factor to the greatest extent possible. Nothing, repeat!, nothing will ever eliminate human error but it can be mitigated to a great extent with some fore thought.