After re-reading my last post and comments, I wanted to emphasize something that might have been lost. Drill rigs are dangerous and need to be respected.
The worst drilling accident that happened on my watch (not the rig I was personally overseeing) involved a lost fingernail (eew) and not anything bigger/more permanent. The worst accident my drillers have been in NOT actually involving a drill rig...well it's actually sort of long, so I'll leave it for later, but it wasn't catastrophic.
With that said, I have a co-worker with an immediate family member who was killed in a drilling accident. I've occasionally used a certain drilling company that lost a driller in an accident. A driller was killed working for one of our extremely large clients (the driller was not geographically close to us and was working for a different firm) at the same time I was also overseeing drilling for the same client. One of my coworkers oversaw a "near miss" where a high-pressure line came lose and hit the driller (in the head) so hard he flew backward 15 feet. He probably survived because he was wearing a hard hat.
All the examples above are within the last 15 years, so they're not exactly ancient history. They generally didn't involve bottom-of-the-barrel drilling companies or inexperienced drillers.
Whenever an accident happened that caught the eye of my company, they would re-examine their safety regulations and usually they would add in a qualifier or another step for the safety check. The problem is that over time, the safety checklists got more elaborate and the pre-drilling procedure that we'd need to tell every driller about got longer and longer. Having a daily pre-drilling inspection that includes random fluid levels (do I really care how much windshield washer fluid they have?) and a 10-minute rig startup procedure just means that people gloss over/forget the really important stuff.
So, here's the short geologist patented guide to avoiding rig mortality:
Take a long look around you. Thunder/lighting? Big heavy rainclouds? Pools of water? Random ropes and heavy equipment? Tuck things away if possible. Make sure folks can skedaddle safely if they need to.
Take a walk around the rig. Chances are you don't know what all the knobs and doohickeys do, but if something looks like it's leaking/rusted through/missing, pull the driller aside and ask about it. If they assure you on their mother's grave, cross their heart and hope to die that it's fine, well, then keep an eye on it and don't stand next to it.
Make sure everything looks reasonably secure on the rig.
Any dangers/problems specific to whatever you're going to do? Mention it to the driller AND helper.
Where is everybody? Fingers and toes free of potential problems? Wearing appropriate gear?
Everybody's been told drilling is about to start?
Find a place to stand/set up that isn't in anybody's way and that avoids obvious pitfalls.
Ok, now you can start.
Repeat process when you think of it or at least hourly. It takes about half a minute to do a quick scan of everything and make sure it looks ok. Remember, long checklists cover your ass, but a little bit of awareness can save it.