Dangerous Statement

Posted by Willy on Apr 27, 2007


After reading your "Safe Boatbuilding" Article on the tips page I felt I should point out a potentially hazardous paragraph:

"Chemical Myths

There are various chemical myths that have been repeated many times. The wildest one I know is that mixing household ammonia and household bleach produces mustard gas. Mustard gas is a compound of carbon, hydrogen, chlorine, and sulfur. Ammonia is a compound of nitrogen and hydrogen.

Bleach (sodium hypochlorite) is a compound of sodium, chlorine, and oxygen. Creating the carbon and sulfur needed for mustard gas from these chemicals would be an achievement that far exceeds any nuclear fission or fusion. All our energy problems would be forever solved.

The truth of the matter is bleach and ammonia (both are 5% solutions in water) generates a little heat and gives off mostly ammonia fumes." _______________________________________________

This myth is not a myth, but a misquoted truth. Chlorine and Ammonia do not form Mustard Gas - True

But the combination of these two chemicals does produce another WWII chemical weapon (In small amounts) - Chlorine Gas. (Probably where the Mustard Gas myth came from)

Chemical Reaction: 2NaOCl (Bleach) + 2NH3 (Ammonia) --> 2NaONH3 + Cl2 (Chlorine gas)

(Side Note: Mixing Bleach and Acids (such as many commercial toilet bowl cleaners or vinegar) will produce LARGE amounts of Chlorine Gas) _________________________________________________

The rest of the story: Chlorine gas formation is mearly a side reaction of the combination of these two materials. When combined, the vast majority of these two materials are consumed in an entirely different series of reactions; the formation of Chloramines.

NH3 + OCl(-) ------> NH2Cl + OH(-) NH2Cl + OCl(-) ------> NHCl2 + OH(-) NHCl2 + OCl(-) ------> NCl3 + OH(-)

Chloramine Gases are extremely toxic and their odor can be mistaken for ammonia fumes. As such, these reaction products are much more dangerous than an ominous green gas (We'd all run from a green gas cloud :)

Exposure to high concentrations of chloramine gases can and does kill people every year largely due to the fact that these materials are often combined in confined areas such as the bathroom or a shower stall. _________________________________________________

After reading the article I got the feeling that some may read that paragraph and come away with: "Oh, so mixing bleach and ammonia is OK - I've been worried about that myth my whole life"

This is clearly not the case and may lead some down a very dangerous path...

To re-iterate - Never mix cleaning agents! It's not a myth... It's a strong warning.

Willy (Boatbuilder / Chemist)

P.S. This can all be confirmed on the internet in various locations. See Wikipedia "Bleach" or Chemistry.about.com.