Mixing bleach and ammonia is extremely dangerous and can be life-threatening. When bleach is mixed with ammonia, toxic gases called chloramines are produced, which can cause coughing, nausea, shortness of breath, watery eyes, chest pain, irritation to the throat, nose, and eyes, wheezing, pneumonia, fluid in the lungs, and even coma and death in high concentrations. The Centers for Disease Control and Prevention (CDC) reported a death from mixing bleach and ammonia, although it is very rare. If you accidentally mix bleach and ammonia, you should move to a safe, well-ventilated area immediately and carefully follow cleanup instructions from your local poison control center. To prevent accidental poisoning with bleach and ammonia, you should store them in their original containers and never mix them with other cleaners, acids, or products that contain them.