Byproducts of the chemical reaction between the ‘bad’ components and the oxidizers form each time one of those ‘bad’ components gets eliminated and we call the disinfection byproducts. See below for a list of the ones listed in the National Primary Drinking Water Regulations for Disinfection ByProducts along with their MCL’s (Maximum Contaminat Levels) and potential hazards to humans:

• Bromate — Associated with an increased risk of cancer. Maximum Contaminant Level: 0.01 mg/L
• Chlorite — Associated with Anemia; infants and young children: nervous system effects. Maximum Contaminant Level: 1.0 mg/L
• Haloacetic acids (HAA5) — Associated with an increased risk of cancer. Maximum Contaminant Level: 0.06 mg/L
• Total Trihalomethanes (TTHMs) — Associated with liver, kidney or central nervous system problems; increased risk of cancer. Maximum Contaminant Level: 0.08 mg/L

The process by which oxidizers break down organic contaminants generates compunds known as ‘disinfection byproducts’: Trihalomethanes (THM’s), Haloacetic Acids (HAA5), Bromates, and Chlorites.

Trihaloemethanes (THM): chloroform, bromodichloromethane, dibromochloromethane, and bromoform.

“EPA has published the Stage 1 Disinfectants/Disinfection Byproducts Rule to regulate total trihalomethanes (TTHM) at a maximum allowable annual average level of 80 parts per billion. This standard will replace the current standard of a maximum allowable annual average level of 100 parts per billion in December 2001 for large surface water public water systems. The standard will become effective for the first time in December 2003 for small surface water and all ground water systems.” (source)

Haloacetic Acids (HAA5): monochloroacetic acid, dichloroacetic acid, trichloroacetic acid and others.

“EPA has published the Stage 1 Disinfectants/Disinfection Byproducts Rule to regulate HAA5 at 60 parts per billion annual average. This standard will become effective for large surface water public water systems in December 2001 and for small surface water and all ground water public water systems in December 2003.” (source)

Bromate:

“Bromate is a chemical that is formed when ozone used to disinfect drinking water reacts with naturally occurring bromide found in source water. EPA has established the Stage 1 Disinfectants/Disinfection Byproducts Rule to regulate bromate at annual average of 10 parts per billion in drinking water. This standard will become effective for large public water systems by December 2001 and for small surface water and all ground public water systems in December 2003.” (source)

Chlorite:

“Chlorite is a byproduct formed when chlorine dioxide is used to disinfect water. EPA has published the Stage 1 Disinfectants/Disinfection Byproducts Rule to regulate chlorite at a monthly average level of 1 part per million in drinking water. This standard will become effective for large surface water public water systems in December 2001 and for small surface water and all ground water public water systems in December 2003.” (source)

Health officials and medical professionals have studied the effects of disinfection byproducts since the mid 1970’s and have found that in large doses, laboratory animals have developed serious, and sometimes deadly, health conditions. With regard to the effects these compunds have on humans, these same health officials and medical professionals have deterined that the current empirical evidence indicates a potential danger to humans and thus a need for additional research and study.

They also believed that the empirical data had enough merit to warrant restrictions on the amounts of disinfection byproducts in drinking water: Stage 1 Disinfectants/Disinfection Byproducts Rule.

“In sum, EPA believes the weight-of-evidence presented by the available epidemiological studies on chlorinated drinking water and toxicological studies on individual disinfection byproducts support a potential hazard concern and warrant regulatory action at this time such as that taken in the Stage 1 Disinfectants/Disinfection Byproducts Rule.” (source)