Arsenic is a popular component of wood preservatives. Many fertilizers also contain arsenic as do many paints, rugs and soaps. Many people who work with these substances in an industrial setting may experience problems related to the long-term exposure. This can include skin cancer, lung cancer, kidney cancer and bladder cancer. Individuals may notice changes to the skin such as thickening and color changes. Arsenic poisoning is an often a deliberate criminal act. Victims may experience severe stomach cramps and nervous system problems and eventually may die. Their murders usually use a pesticide or fertilizer as the poisoning agent. Because arsenic occurs naturally, many water supplies some level of contamination. According to the Environmental Protection Agency, arsenic is more common in ground water than in lakes and rivers. People who use wells are in danger of finding high levels in the water supply. The EPA's standard for arsenic level is 10 parts per billion.