Most people think arsenic is just a poison used to kill rodents and in some Hollywood movies - spouses! But arsenic occurs naturally in the soil and bedrock and is higher in some states than others. While public water systems are required to monitor arsenic levels in the water, some water supplies will be exposed to high arsenic levels if arsenic leaks into water wells, which often are private. Exposure to high arsenic level in drinking water caused chronic arsenic poisoning. Long-term exposure to arsenic in drinking water increases a person's changes of getting skin, bladder, lung, liver, colon, and kidney cancer. Health officials say arsenic exposure may also cause blood vessel damage, high blood pressure, nerve damage, anemia, stomach upsets, diabetes, and skin changes. While arsenic is also present in wood products and is used in glass production, the most serious health effects seem to come from exposure through the water supply.