02/24/2009 US EPA COMMON HEALTH QUESTIONS RELATED TO MONOCHLORAMINE 21) Can I shower in or use a humidifier with chloraminated water? Chloraminated water that meets EPA standards is safe to use for showering. • Showering with chloraminated water poses little risk because monochloramine does not easily enter the air. • Trichloramine1, a chemical related to monochloramine and often found in swimming pools, enters the air more easily and has been linked to breathing problems. • Trichloramine may form more easily in swimming pools because of higher levels of chlorine as well as ammonia from bodily fluids that are often found in swimming pools.2 Chloraminated water that meets EPA standards is safe for use in humidifiers. • The use of chloraminated water in humidifiers poses little risk because monochloramine does not easily enter the air. • EPA is not aware of any studies that investigate the use of disinfected water in humidifiers. • It is important to follow the manufacturer's instructions regarding proper maintenance and operation of your humidifier. EPA considered a wide range of household uses in establishing regulatory limits for chloramines in water. • EPA considered all available research in establishing regulatory limits for chloramines in water.3 • EPA considered historical data in establishing regulatory limits for chloramines in water.3 • EPA's regulatory standard for chloramines provides a wide margin of safety4 to offset any uncertainties in risk assessments. Additional Supporting Information: 1. Trichloramine formation does not usually occur under normal drinking water treatment conditions. However, if the pH is lowered below 4.4 or the chlorine to ammonia-nitrogen ratio becomes greater than 7.6:1, then trichloramine can form. Trichloramine formation can occur at a pH between 7 and 8 if the chloramine to ammonia-nitrogen ratio is increased to 15:1. Source: Optimizing Chloramine Treatment, 2nd Edition, AwwaRF, 2004. 2. Problems with trichloramine have been most-often associated with indoor swimming pools and are known to cause a strong chlorine-type odor. Trichloramine can be controlled in indoor swimming pools with proper pool maintenance and ventilation. For more information see: http://www.cdc.gov/healthyswimming/irritants.htm. 3. More information on EPA's standard setting process may be found at: http://www.epa.gov/OGWDW/standard/setting.html. 4. For additional information regarding how uncertainty factors (also known as safety factors) are applied to risk assessments to provide a wide margin of safety see: http://epa.gov/risk/dose-response.htm. ------- |