It IS about the tech level, but it is also about the roll of the dice. Sometimes the simplest solutions, mixed by masters, blow up (or don't get made at all?) while the trickier, more potent potions are made with ease by trainees. I'm pretty sure the blowing up is a RANDOM event, made less frequent only by upgrading the alchemy level. I still haven't purchased level 3 alchemy, but I rarely make potions anymore. When I have lab accidents, I just keep trying and make the extra healing potions between to help the recovery of my victims.

miskinsincap - the funniest is watching the elderly "run" from the lab. Everyone else has settled down and gone back to work while they are still making their "escape" out the ENTRANCE of the lab! I've learned to put the elders in the bath before mixing up potions, just in case. LOVE watching them do the back float!

Tech level just reduces the chances of potions blowing up. Which potions actually blow up is completely random.

I had to finally break down and buy level 3 Alchemy. I would have potion after potion blow up, one right after the other, so back to work for level 3 Nature. *sigh* The idea about the elderly is a good one. Thank you!

One of my potions blow up and killed myfav vilenger

This is interesting information. I didn't know that was possible. I almost killed a villager by making her make a potion that blew up three times in a row. I wasn't paying attention to her and would check back and see no potion so I made her remake it again and again. I finally looked at her health bar and it was zero. I'm glad I didn't kill her that way. She's dead now but of natural causes.