Arsenic is found in nature at low levels. It's mostly 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.
Most arsenic compounds have no smell or special taste. Inorganic arsenic compounds are mainly used to preserve wood. They are also used to make insecticides and weed killers. You can check the labels of treated wood and insecticides to see if they contain arsenic. Copper and lead ores contain small amounts of arsenic.