Dioxin

• One by-product of chlorine and chlorine-based cleaning supplies can be dioxin. Dioxin is a far more potent carcinogen than the banned pesticide DDT. Dioxins can form as the chlorinated bleach combines with other materials. Dioxins do not break down and remain in the environment for many years.
  
  

Chloroform

• Using chlorine-based bleach in the laundry can result in another carcinogen, chloroform. However, the levels of chloroform created through the use of chlorine bleach in the laundry are relatively small. It is unclear whether these chloroforms are sufficient to cause cancer.
  
  

Corrosive

• Chlorine-based bleaches are corrosive and often labeled as such. Chlorine bleaches must be diluted or they can cause skin burns and irritation and damage other home surfaces.
  
  

Mixed With Ammonia

• If chlorine bleach comes into contact with ammonia, the resulting mixture usually results in the creation of chlorine gas. Chlorine gas is very toxic, and deaths resulting from the unintentional mixing of chlorine bleach and ammonia have occurred. Chlorine gas tears nasal passages, the trachea and lungs by causing massive cellular damage. If you have both chlorine bleach and ammonia in your home, you must be very careful that everyone is aware of this potentially lethal by-product.
  
  In addition to chlorine gas, mixing chlorine with ammonia can result in nitrogen tetrachloride. Any tetrachloride is a highly toxic substance. Nitrogen tetrachloride is also highly explosive. Another explosive potential by-product of a chlorine-ammonia mixture is hydrazine.
  
  

Mixed With Acids

• Chlorine gas can also be formed when chlorine bleach mixes with certain household cleaners that contain acid, like vinegar and some drain cleaners or scouring products. This can be especially dangerous if the bleach contains chemicals to mask the chlorine smell.