¡Ácido nítrico!

OH went to the local shop to buy some aguafuerte to clear the drains, something we've done before, and very effective as long as you don't inhale it or get any on your skin. He said "what symbol would you expect to see on a bottle of strong acid?". I suggested biohazard or something with flames or explosions. However, the packaging has changed to feature a cheerful little rodent in colourful clothes looking ready for fun, albeit with (if you look closely) protective gloves and what may be a mask in one hand. For anyone with young children, this looks like a tragedy waiting to happen - how can this be allowed?
Now after googling nitric acid I expect to be on a list for terrorists and home-made explosives....
Postscript - some bottles of aguafuerte may be concentrated hydrochloric acid, not nitric. So that's OK then....