<Dl> <Dt> Chemical hazard </Dt> </Dl> <Dl> <Dd> A chemical can be considered a hazard if by virtue of its intrinsic properties it can cause harm or danger to humans, property, or the environment . </Dd> <Dd> Health hazards associated with chemicals are dependent on the dose or amount of the chemical . For example, iodine in the form of potassium iodate is used to produce iodised salt . When applied at a rate of 20 mg of potassium iodate per 1000 mg of table salt, the chemical is beneficial in preventing goiter, while iodine intakes of 1200--9500 mg in one dose have been known to cause death . Some chemicals have a cumulative biological effect, while others are metabolically eliminated over time . Other chemical hazards may depend on concentration or total quantity for their effects . </Dd> <Dd> A variety of chemical hazards (e.g. DDT, atrazine, etc .) have been identified . However, every year companies produce more new chemicals to fill new needs or to take the place of older, less effective chemicals . Laws, such as the Federal Food, Drug, and Cosmetic Act and the Toxic Substances Control Act in the US, require protection of human health and the environment for any new chemical introduced . In the US, the EPA regulates new chemicals that may have environmental impacts (i.e. pesticides or chemicals released during a manufacturing process), while the FDA regulates new chemicals used in foods or as drugs . The potential hazards of these chemicals can be identified by performing a variety of tests prior to the authorization of usage . The amount of tests required and the extent to which the chemicals are tested varies, depending on the desired usage of the chemical . Chemicals designed as new drugs must undergo more rigorous tests that those used as pesticides . </Dd> <Dd> Some harmful chemicals occur naturally in certain geological formations, such as radon gas or arsenic . Other chemicals include products with commercial uses, such as agricultural and industrial chemicals, as well as products developed for home use . Pesticides, which are normally used to control unwanted insects and plants, may cause a variety of negative effects on non-target organisms . DDT can build up, or bioaccumulate, in birds, resulting in thinner - than - normal egg shells which can break in the nest . The organochlorine pesticide dieldrin has been linked to Parkinson's disease . Corrosive chemicals like sulfuric acid, which is found in car batteries and research laboratories, can cause severe skin burns . Many other chemicals used in industrial and laboratory settings can cause respiratory, digestive, or nervous system problems if they are inhaled, ingested, or absorbed through the skin . The negative effects of other chemicals, such as alcohol and nicotine, have been well documented . </Dd> </Dl> <Dd> A chemical can be considered a hazard if by virtue of its intrinsic properties it can cause harm or danger to humans, property, or the environment . </Dd> <Dd> Health hazards associated with chemicals are dependent on the dose or amount of the chemical . For example, iodine in the form of potassium iodate is used to produce iodised salt . When applied at a rate of 20 mg of potassium iodate per 1000 mg of table salt, the chemical is beneficial in preventing goiter, while iodine intakes of 1200--9500 mg in one dose have been known to cause death . Some chemicals have a cumulative biological effect, while others are metabolically eliminated over time . Other chemical hazards may depend on concentration or total quantity for their effects . </Dd>

Potential hazards that can occur in computer environments