The U.S. Environmental Protection Agency, EPA, has added nine hazardous waste sites to its National Priorities List of Superfund sites - those that pose the most complex and hazardous threat - and is proposing to add another eight. The listings provide policymakers with a lists of high priority sites so that they can determine the size of the challenge, the EPA said.

For all the sites, the agency said it first works to identify companies or people responsible for the contamination and requires them to conduct or pay for the cleanup. The sites newly listed or proposed for listing include two former oil refineries, a chemical drum recycling plant and two sites belonging to chemical producers Troy Chem Corp and Unimatic Manufacturing Corporation, both in New Jersey.

Since 1983, the EPA has listed 1,694 sites. At about 68% a cleanup is said to be in progress.