Brownfield is a term used in urban planning to describe land previously used for industrial purposes or some commercial uses. Such land may have been contaminated with hazardous waste or pollution or is feared to be so. Once cleaned up, such an area can become host to a business development such as a retail park. Land that is more severely contaminated and has high concentrations of hazardous waste or pollution, such as a Superfund site, does not fall under the brownfield classification. Mothballed brownfields are properties that the owners are not willing to transfer or put to productive reuse.