Bleach, acids and alkaline-based products can injure as they clean.
By Mohamud Daya, M.D., and David B. Chandler, pH.D.
Most commercial cleaning products if used as directed by the manufacturer's labels should not produce any significant health effects. However, a number of these products have the potential to produce a variety of adverse health effects if used improperly (incorrect dilution or application) or if mixed with other cleaning agents.
One of the most common is bleach. The active ingredient in most products containing bleach is sodium hypochlorite in concentrations ranging from 3 percent to 6 percent (with a pH level up to 11.0).
Some bleach solutions may also contain silicate (15 percent to 17 percent) and sodium carbonate (60 percent) and have a pH of 10.5. Bleaching agents are effective because they react with atmospheric carbon dioxide to produce hypochlorous acid, which chemically decomposes to produce oxygen free radicals.
Oxygen free radicals are believed to be responsible for the bleaching and disinfecting activity as well as the toxic effects associated with these compounds.
Symptoms following exposure to bleach will depend on the volume, viscosity, pH, concentration, and duration of contact. As an oxidizing agent, sodium hypochlorite is corrosive to tissue. Solutions containing less than 6 percent sodium hypochlorite will cause significant injury only after prolonged or extensive exposure.
However, concentrated solutions can produce more severe tissue injury with less-extensive exposure. Skin or eye exposure produces local burning and irritation. Inhaling sodium hypochlorite fumes may lead to sore throat, cough, wheezing, shortness of breath, and pulmonary edema (fluid in the lungs).
Ingesting household bleach can cause oral, esophageal and gastric burns as well as produce nausea, vomiting, diarrhea and abdominal pain.
Toilet bowl cleaners contain various concentrations of corrosive agents, including such compounds as sulfuric acid (80 percent), hydrochloric acid (10 percent to 25 percent), oxalic acid (2 percent) or sodium bisulfate (70 percent to 100 percent).
Other acid-containing products which are corrosive in nature include drain cleaners (sulfuric acid or sodium hydroxide), metal cleaners and anti-rust compounds (hydrofluoric, phosphoric, oxalic, hydrochloric, sulfuric or chromic acids). The cleaning properties associated with these products are thought to stem from the corrosive nature of these compounds.
Symptoms following exposure to any of them will depend on the route, concentration and duration of contact. Acids produce their corrosive effects by directly damaging the surface layers of tissues. Except for hydrofluoric acid, the surface injury produced by acids prevents further penetration of the skin, limiting the extent of injury.
Effects to the skin following exposure can range from reddening and swelling to blister formation and overt skin destruction. Eye exposure may result in burning, pain, redness and corneal damage.
Inhaling acid fumes can cause sore throat, coughing, wheezing and shortness of breath. Severe exposure can lead to pulmonary edema, although this is not likely to occur with most household cleaning products.
Ingestion can lead to severe oral, esophageal and/or gastric burns, nausea, vomiting and abdominal pain.
Ammonia-based cleaning products are also frequently used in commercial settings. These products are classified as alkaline (caustic) and contain from 3 percent to 10 percent ammonium hydroxide.
Other alkaline cleaning products include drain cleaners (sodium hydroxide), automatic dishwashing detergents (sodium tripolyphosphate, sodium metasilicate, sodium silicate, sodium carbonate) and oven cleaners (sodium hydroxide). The caustic nature of these compounds is thought to account for their cleaning properties.
The clinical effects from exposure to caustic compounds will depend on the concentration and the amount of contact. Alkaline agents directly damage tissues.
But unlike acid solutions, alkaline solutions have the potential for more serious tissue damage because their ability to solubilize skin fats and proteins lets them penetrate more deeply.
Skin contact with an alkaline solution will produce a soapy feel and result in severe pain, blister formation, and tissue destruction. Eye exposure may bring burning, pain, redness and severe corneal injury.
Inhaling ammonia or other alkaline fumes will produce burning pain in the nose, mouth, throat and chest. More severe exposure can cause hoarseness, coughing and difficulty in breathing. Ingestion can lead to severe oral, esophageal and/or gastric burns, nausea, vomiting and abdominal pain.
Mixing Cleaning Products
While casual exposure to any of these products can be dangerous, exposure to a combination of them can be deadly. In an attempt to make cleaning products work better and faster, workers have been known to mix multiple cleaning agents. But indiscriminate mixing of products can lead to the release of toxic gases.
For example, if bleach is mixed with an acid-containing toilet bowl cleaner, the result will be the release of deadly chlorine gas. If bleach is mixed with an ammonia-based cleaning agent, harmful chloramine gas -- both monochloramine and dichloramine -- will be generated.
The amount of damage depends on how much was inhaled -- and for how long. Chlorine gas reacts with water-containing tissues (eyes, mouth and lungs) to produce hypochlorous acid and oxygen free radicals.
Exposure to low concentrations of chlorine -- 1 to 10 parts per million (ppm) -- may cause burning of the eyes, sore throat and cough. Higher concentrations (30 to 50 ppm) can lead to more severe coughing, shortness of breath, wheezing and pulmonary edema. If chlorine vapors become trapped in clothes, they can cause skin injury.
Anyone exposed to chlorine gas should be moved quickly to fresh air. This must be done cautiously to avoid exposing to rescuers to the fumes.
Individuals with significant skin exposure should have their clothes removed and skin washed thoroughly. In most instances, symptoms will disappear once the exposure ends. Persistent symptoms need to be further evaluated.
Similarly, when chloramine gas contacts the mucous membranes, it forms hypochlorous acid and oxygen free radicals -- potent oxidizing agents -- that produce direct injury to whatever tissue they contact. Because chloramine cannot be washed away as easily as chlorine, it can cause more serious damage.
Cleaning in confined spaces such as restrooms in the presence of chloramine gas can result in cough, sore throat, wheezing and pulmonary edema. Those exposed to the gas should be removed and treated like victims of chlorine gas exposure.
Most commercial cleaning products contain low concentrations of bleach, corrosives or caustic substances and are not likely to be health hazards if used properly. However, the mixing of bleach with acid- or ammonia-containing cleaning products can be fatal. Workers should be warned and discouraged from mixing any cleaning products.
Mohamud Daya, M.D., is medical director and David B. Chandler, Ph.D, is director of Chemical and Risk Information System at the Oregon Health Sciences University in Portland, OR.