These efforts are to achieve the delisting of the areas of concern, and it's anticipated that the goal of delisting them will be achieved by 2025. Sometimes you do all the remediation that it is possible to do and then you have to leave the site to recover over time. The delisting will take place when the ecosystem is totally restored, but the cleanup activities and the restoration activities are finished sometime before that.
On March 4th, 2014. See this statement in context.