Annual federal appropriations to the EPA’s Superfund program have declined, from about $2 billion in 1999 to about $1.1 billion in 2013, according to a report from the US Government Accountability Office.

The study also finds EPA site-specific cleanup spending on remedial cleanup activities at nonfederal National Priorities List (NPL) sites declined from about $0.7 billion to about $0.4 billion during the same time period.

Remedial cleanup activities include remedial investigations, feasibility studies, and actions taken to clean up a site.

The total number of nonfederal sites on the NPL increased from 1,054 in fiscal year 1999 to 1,158 in fiscal year 2013, and averaged about 1,100 annually. The number of remedial action project completions at nonfederal NPL sites declined by about 37 percent during the 15-year period. Similarly, the number of construction completions at nonfederal NPL sites generally declined by about 84 percent during the same period.

Last week 12 private parties agreed to pay more than $3.5 million to clean up a Superfund site in Pennsylvania as part of a settlement with the EPA. ExxonMobil, BP, DuPont, Veolia and eight others are among the 12 settling parties will pay an estimated $2.5 million for the investigation and an estimated $1 million to remove contaminated soil at Metro Container Superfund Site in Trainer, Pennsylvania.