Arsenic is found in the environment in its naturally-occurring form and as a by-product of the manufacturing and application of arsenic-containing chemicals. Arsenic-related compounds and alloys have been used in the manufacture of a wide variety of products including pesticides, wood preservatives, glass products, batteries, semiconductors, ammunition and medicine. Highly toxic and a known carcinogen, sources of arsenic contamination include industrial and workplace exposure, ingestion of food and water containing arsenic-related substances and contact with products containing the chemical.

Preservation of wood products using Chromated Copper Arsenate (CCA) is one of the most pervasive uses of arsenic-related chemicals. CCA-treated wood has been widely used in the construction of houses, decks, playground structures, fences, picnic tables and products designed for use outdoors. By 2004, public concerns about CCA exposure resulted in the phasing out of CCA use in residential building materials.

When found above certain levels, arsenic in drinking water can pose significant health hazards. Arsenic-related toxins contaminate the water supply through industrial run-off,  improper disposal of hazardous waste and by the leaching of the metal through contaminated soil. Clear, odorless and tasteless, arsenic contaminants in drinking water are detectable only through laboratory testing.

Ingestion or exposure to arsenic at high enough levels is a known cause of lung, bladder, liver, kidney and skin cancer and can damage the immune, nervous and vascular systems.  It is also a suspected hormone disruptor.

Measures to prevent or minimize exposure to arsenic-related compounds include:

• Check with your local water authorities for information about tests done for arsenic detection; if you use well water, have a sample tested.  
• Monitor children’s activities at playgrounds with wooden structures; discourage them from putting their fingers in their mouths after contact with treated wood or the soil around it; make sure children wash hands thoroughly after coming in from outside. 
• Annually seal decks, fences or other materials constructed from treated wood. 
• Avoid painting treated wood and minimize sawing or other activity which could release contaminants into the environment. Do not burn treated wood; ash and residue left behind will contain high concentrations of arsenic. 
• Avoid contact with soil under or near treated wood where arsenic may have leached into the ground.
• Remove shoes before entering your house after contact with treated wood surfaces. 
• Wash hands thoroughly after handling treated wood.
  

Sources:

• EPA
• Toxnet - Official Citation: Report on Carcinogens, Eleventh Edition; U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program 
• Alliance for Healthy Homes
• The Agriculture and Public Health Gateway