familiar solutions

I have a project. It started with a certain telephone technician. Lets say, he was digging a hole for a new telephone pole. When he had finished his hole, he discovered some kind of petrol/diesel smelling product on the surface of the water in the hole. This discovery meant that he could not install his telephone pole, and possibly someone would not be able to make phone calls or log onto the internet. This immediately alerted him to a potential pollution problem (I just invented a tripple p reference there ... haha). Anyways, I was handed the project. I started with the usual investigation, including asking questions and trying to reconstruct what could have led to this tripple p. As I write this, I'm at the end of my investigation. The lab results are in and the drawings have been prepared. The conclusion is that there is no potential pollution problem. The results are all zero. No source of fuel has been found in the vicinity of the telephone pole that can be correlated or associated with what he claimed to have seen. Here are some questions and scenarios I've been thinking on:

1. The telephone technician didn't really see any kind or petrol/diesel

2. The petrol/diesel that he claimed to have seen is now gone

3. The petrol/diesel is probably still there, I perhaps just missed it

See, I like option 2 because it makes this a straight forward project. Consequently I'm tempted to say there is no tripple p. But a fundamental problem arises here. That is; when we are faced with life problems which have the potential to go either way, we seem happy to settle for familiar solutions. I worry that if this principle persists, we'll end up with solutions that are familiar but not necessary correct or accurate.