Muriatic acid fumes [closed]

hello me and my 6 year old cousin were cleaning sea shells in my garage in 300 ML of water that had 3 drops of muriatic acid in it the cup tipped over and spilled it evaporated pretty quickly are we in any danger from the fumes

• Three drops in 300 mL water? That's not a hell of a lot. Don't worry, but don't forget to wash your hands before you rub your eyes :) – Klaus-Dieter Warzecha Feb 4 '17 at 19:10
• Not sure how old you are, but I'm concerned about how you got the three drops. The container of muriatic acid itself is unsafe. Muriatic acid typically has a lot of iron so it is no good for a chemistry lab. However it is almost as concentrated as concentrated HCl that a chemist would use. Just use vinegar next time and wear safety glasses or goggles to protect your eyes. – MaxW Feb 4 '17 at 19:21
• Also cleaning sea shells in acid is a silly idea. They are made of calcium carbonate so they will react with the acid. – bon Feb 4 '17 at 23:03

3 drops of hydrochloric acid (muriatic acid) is probably a volume less than $0.3 ~\pu{ml}$. $0.3 ~\pu{ml}$ acid in $300 ~\pu{ml}$ water is a dilution of $1 : 1000$.
If the acid was concentrated muriatic acid (e.g. $10 ~\pu{mol/l}$) the resulting diluted acid had a concentration of about $0.01 ~\pu{mol/l}$. This concentration is much less than that of gastric acid ($0.05 - 0.1 ~\pu{mol/l})$. The diluted acid itself is not dangerous.
About the fumes: 3 drops of concentrated hydrochloric acid contain about $70 ~\pu{ml}$ of the gas hydrogen chloride ($\ce{HCl}$). If you would completely inhale this volume it would be dangerous. If the same volume is uniformly distributed in a room of $> 35 ~\pu{m^3}$ it would result in an acceptable concentration.