Documented Health Risks of Chlorine and Other Toxic Chemicals

while Showering or Bathing

When chlorine is used as a water treatment, it combines with organic matter to form compounds called trihalomethanes (THMs), also known as disinfectant byproducts (DBPs). One of the most common THMs formed is chloroform, which is a known carcinogen. (1) Other THMs formed include the di- and trichloramines formed when chloramine is used as a disinfecting agent. (2) These compounds are toxic when consumed, inhaled, or applied to the skin.
Humans are exposed to DBPs through drinking-water and oral, dermal, and inhalational contact with chlorinated water (3). In populations who take hot showers or baths, inhalation and dermal absorption in the shower accounts for more exposure to THMs than drinking water (4).

Documented Health Risks:

  • Bladder Cancer and Exposure to Water Disinfection By-Products through Ingestion, Bathing, Showering:

  • Bladder cancer has been associated with exposure to chlorination by-products in drinking water, and experimental evidence suggests that exposure also occurs through inhalation and dermal absorption. read published article hereand here

  • Cancer risk associated with household exposure to chloroform:

  • Chloroform (CHCl3) the trihalomethane most prevalent in drinking water, is a proven animal carcinogen and a suspected human carcinogen.. read published article here…

  • Cancer risk from the inhalation exposure to chloroform during showering:

  • Risk from exposure to trihalomethanes during shower:

  • Exposure to trihalomethanes (THMs) through inhalation and dermal contact during showering and bathing may pose risks to human health. This study predicted cancer incidents from exposure to THMs during showering…read published article here more…


  • Richer people with higher levels of schooling are actually increasing their risk of THM exposure:

  • High levels of trihalomethanes (THM), chemicals formed in chlorinated water, have been implicated as a possible risk factor for cancer and can be ingested through public drinking water supplies, or absorbed through the skin in baths, showers, and public swimming pools. read published article here…

  • Trihalomethanes increase significantly in the bloodstream after showering, a new study shows:


  • Inhalation is an important exposure route for volatile water contaminants, including disinfection by-products (DBPs). A controlled human study was conducted on six subjects to determine the respiratory uptake of haloketones (HKs) and chloroform, a reference compound, during showering. read published article here more…

  • Changes in breath trihalomethane levels resulting from household water-use activities:

    Common household water-use activities such as showering, bathing, drinking, and washing clothes or dishes are potentially important contributors to individual exposure to trihalomethanes (THMs), the major class of disinfection by-products of water treated with chlorine. read published article here more…

  • Inhalation exposure to haloacetic acids and haloketones during showering:

    Inhalation exposure to haloacetic acids (HAAs – a by-product of chlorine) and haloketones (HKs) (a harmful type of chlorination disinfection by-products – CDBP) in contaminated drinking water occurs during showering. read published article here more….


  • Study shows showering boosts concentrations of potentially hazardous trihalomethanes:

    Trihalomethanes — byproducts of interaction between chlorine used to disinfect water and organic matter found in raw water — increase significantly in the bloodstream after showering, a new study shows. read published article here more….


  • Indoor Air and Internal Dose Levels of Trihalomethanes:

    Individual exposure to trihalomethanes (THMs) in tap water can occur through ingestion, inhalation or dermal exposure. Studies indicate that activities associated with inhaled or dermal exposure routes result in a greater increase in blood THM concentration than ingestion. Previous studies of these exposure routes have focused primarily on the activities of showering and bathing. In this study, we determined the relative contribution of other household water use activities for THM exposure assessment. read published article here….

  • Percutaneous absorption of trihalomethanes, haloacetic acids, and haloketones:

    Bathing in chlorinated drinking water causes significant exposure to potentially toxic disinfection by-products (DBPs).Dermal absorption is an important route of exposure to THMs and HKs and must be considered in models of risk assessment. read published article here….