• Arsenic is a naturally occurring element in the earth’s crust, and can be organic or inorganic depending on the other elements it is combined with.
• The main use for arsenic is in pesticides and weed killers.

Arsenic is a naturally occurring element in the earth’s crust, such as in copper and lead ores, where it is usually found in compounds with oxygen, chlorine, and sulfur. These are called inorganic arsenic compounds. Arsenic in plants and animals combines with carbon and hydrogen. This is called organic arsenic. Organic arsenic is usually less harmful than inorganic arsenic. Pure arsenic is a gray-colored metal, but this form is not common in the environment. Most arsenic compounds have no smell or special taste.

The main use of arsenic is for pesticides. Some products, mostly weed killers, use arsenic as the active ingredient. Other pesticides use inorganic forms of arsenic to kill plants, insects, or rodents, or to preserve wood. Persons who manufacture or use these pesticides or handle treated wood may be exposed to arsenic if adequate safety procedures are not followed. Inorganic arsenic is regulated by the Occupational Safety and Health Administration (OSHA) at 1910.1018.

Some facts about arsenic include the following:

• It doesn’t evaporate.
• Most arsenic compounds can dissolve in water.
• It gets into air when contaminated materials are burned.
• It settles from the air to the ground.
• It doesn’t break down, but can change from one form to another.
• Fish and shellfish build up organic arsenic in their tissues, but most of the arsenic in fish isn’t toxic.