What are brownfields?

Brownfields refer to previously developed properties that may be contaminated or perceived to be contaminated and are not being used to their full potential due to the fear of environmental hazards. They are typically abandoned commercial sites where there may be some degree of industrial or commercial pollution that complicates their redevelopment. The identification and rehabilitation of these sites are crucial for urban redevelopment and environmental rehabilitation, making it possible for communities to clean up and repurpose these areas for new, beneficial uses.

The other options do not accurately capture the definition of brownfields. Undeveloped land parcels are simply vacant and have not undergone development, which does not imply any contamination issues. Regulated housing zones refer to areas with specific zoning laws, which can include various types of developments, rather than focusing solely on previously used sites. Foreclosed residential properties pertain to homes that have gone back to a lender due to the owner's inability to pay, but do not involve the complexities surrounding environmental contamination that characterize brownfields.