Hazards of Mixing Household Chemicals Billie Jo Rich Department of Chemistry and Chemical Engineering, South Dakota School of Mines and Technology Rapid City, SD The chemistry at work. The combination of products containing Bleach (NaOCl) with products containing Ammonia (NH 3 ) may release one or more of several toxic compounds. The following are several examples of some of the compounds formed from mixing bleach and ammonia products. When bleach and any acid are mixed, chlorine gas and water are released. Chlorine gas will react with water to form hypochlorous and/or hydrochloric acid. When a bleach product is combined with an ammonia containing product, monochloramine and dichloramine are formed. If these compounds come into contact with water they may form hypochlorous acid. Then may form hydrochloric acid and release nascent oxygen. Nascent oxygen is toxic and has been known to cause respiratory tract infection and pneumonia. Chlorine gas is itself toxic and can cause many problems depending on the severity of exposure. A concentration of at least 3.5 ppm is usually required for odors of chlorine gas to be detected. But, exposure to 1 ppm chlorine gas can be enough to cause mild irritation to the mucous membranes. An exposure level of 3 ppm can cause extreme eye irritation and irritation to the respiratory tract. After an exposure to chlorine gas, reported symptoms include, but are not limited to: dizziness, cough and chest constriction. Hydrochloric and hypochlorous acids can cause burns or tissue damage if a person has a prolonged exposure to them. Monochloramine and dichloramine produce tearing, respiratory tract irritation, and/or nausea. Bleach and ammonia are two common household cleaning products which can cause serious health problems when mixed. The mixing of these two compounds causes the formation of Chlorine gas. Chlorine gas is highly toxic if inhaled. It can cause many respiratory problems which may result in hospitalization or death. Bleach and ammonia are not always found alone. They are both common ingredients on many other cleaning products. They are found in products such as toilet bowl cleaner, Ajax, window cleaners, mildew removers and soap scum removers. The following are reported incidents involving exposures to mixed cleaning products. On December 19, 1987, a patient mopped a bathroom floor with a 4% phosphoric acid solution, then rinsed the floor with water. Immediately after he applied a bleach and water solution to the floor, a noxious gas with a strong odor was emitted. The mixture was poured down a drain, and the floor was again rinsed with water; however, because the room's exhaust fan was inoperative and windows had been sealed shut, the gas dispersed throughout the ward and caused symptoms in other patients. The ward was evacuated; patients and staff returned after 1-1/2 hours when the odor had dissipated. Within an hour of their return, additional patients and staff complained of symptoms including nausea, eye irritation, tearing, sore throat, headache, cough, and chest tightness; one patient had an acute exacerbation of asthma. The ward was reevacuated until the following day. (CDC MMWR weekly) On November 3, 1989, a patient supervised by a new employee was allowed in a locked storage area and poured an undetermined amount of 4% phosphoric acid cleaner into a bucket containing bleach and water, immediately producing a cloud of noxious vapor. The employee, who was exposed to the vapors for less than 1 minute, reported immediate throat and nasal burning that persisted for more than 24 hours, as well as transient dizziness and nausea. Supplemental oxygen was administered at a local acute-care hospital emergency room for 3 hours. The employee completely recovered within 36 hours following exposure. The patient had no symptoms. (CDC MMWR weekly) On December 7, 1988, a patient assisting in janitorial duties mixed bleach with phosphoric acid cleaner. Immediately a noxious gas with a strong odor was detected and prompted the evacuation of two wards for 1-1/2 hours. Fire department personnel using self-contained breathing equipment disposed of the chemicals and ventilated the area. The patient experienced vomiting, cough, and inspiratory discomfort; elevated blood pressure and fever were noted when the patient was treated in the emergency room. Five employees who helped evacuate the ward complained of symptoms including eye irritation and shortness of breath. Employees and patients returned approximately 1-1/2 hours after the area was ventilated. (CDC MMWR weekly) Chem 292, Chemistry Outreach Fall 2000 Dr. David A. Boyles and Dr. M. Steven McDowell Source: CDC MMWR weekly, September 13, 1991,