Why coin cells are highly dangerous to kids

Discarded batteries can usually be disposed of safely via your local authority: if a coin cell is swallowed, go to A&E immediately. © AWI'm reminded by a reader of the danger that button batteries or coin cells pose to kids - if they're swallowed then it should be treated as a medical emergency, call 999 or go straight to A&E.

The problem is that due to electrolytic action, the cell converts salty water - as found maybe in the throat or gut - into caustic soda (Sodium Hydroxide) - known to many as caustic drain cleaner or oven cleaner.  So there's a serious risk of chemical burns in the throat or stomach.

Cheap button batteries are available on large cards for £1 from Pound shops, and are almost bought and treated like sweets -- but parents must make sure they keep button batteries and coin cells away from babies and children. If swallowed, seek emergency advice straight away and don't take No for an answer. More details on this specific problem from BatteryControlled, a website dedicated to promoting awareness of this risk.

You can read more about caustic soda from Dow Chemicals, one of the world's largest chemical manufacturers.

(Update) Here is  a useful link from a US Childrens Healthcare site:

http://www.uwhealthkids.org/news-and-events/coin-batteries-hidden-danger-to-kids/36241

Here's another thread on The Register.