Why Not to Mix Bleach and Ammonia

The chemical reactions involved in mixing bleach and ammonia produce extremely dangerous toxic vapors. Thus, it's important to understand some first aid advice in case you're accidentally exposed to a bleach and ammonia mixture.

Noxious Fumes and Poisonous Reactions

The primary toxic chemical formed by this reaction is chloramine vapor, which has the potential to form hydrazine. Chloramines are a group of related compounds well-known to be respiratory irritants. In addition to respiratory irritation, hydrazine can also cause edema, headache, nausea, and seizures. Mixing bleach and ammonia also produces chlorine gas, which has been used as a chemical weapon.

Two common ways to accidentally mix these chemicals include:

• Mixing cleaning products (generally a bad idea)
• Using chlorine bleach to disinfect water that contains organic matter (i.e., pond water)

Chemicals Produced

Note that each of these chemicals but water and salt is toxic:

• NH₃ = ammonia
• HCl = hydrochloric acid
• NaOCl = sodium hypochlorite (bleach)
• Cl = chlorine
• Cl₂ = chlorine gas
• NH₂Cl = chloramine
• N₂H₄ = hydrazine
• NaCl = sodium chloride or salt
• H₂O = water

Likely Chemical Reactions

Bleach decomposes to form hydrochloric acid, which reacts with ammonia to form toxic chloramine fumes.

First, hydrochloric acid forms.

NaOCl → NaOH + HOCl

HOCl → HCl + O

Next, the ammonia and chlorine gas react to form chloramine, which is released as a vapor.

NaOCl + 2HCl → Cl₂ + NaCl + H₂O

2NH₃ + Cl₂ → 2NH₂Cl

If ammonia is present in excess (which it may or may not be, depending on your mixture), toxic and potentially explosive liquid hydrazine may form. While impure hydrazine tends not to explode, it does have the potential to boil and spray hot, chemically toxic liquid.

2NH₃ + NaOCl → N₂H₄ + NaCl + H₂O

First Aid When Exposed

If you become exposed to fumes from mixing bleach and ammonia, immediately remove yourself from the area to fresh air and seek emergency medical attention. While the vapors may attack your eyes and mucous membranes, the biggest threat derives from inhaling the gases.

1. Get away from the site where the chemicals were mixed. You can't call for help if you are overwhelmed by the fumes.
2. Call 911 for emergency help. If you feel that 911 is unwarranted, call Poison Control at 1-800-222-1222 for advice on handling the effects of exposure and chemical cleanup.
3. If you find someone unconscious who you believe is suffering from inhalation of bleach/ammonia compound, try to remove the person to fresh air, preferably outdoors. Call 911 for emergency assistance. Do not hang up until instructed to do so.
4. Seek proper cleanup and disposal instructions from Poison Control. Such a mistake is most likely to be made in a bathroom or kitchen, so thoroughly ventilate the area before returning to dispose of the compound and start cleanup.