DTSC’s Carefully Worded letter on Oak Creek and contamination issues

Recently, the Department of Toxic Substances Control released a carefully worded letter to the Oak Creek developers KB Homes Sept 11, 2019 . 

While ENU fully supports the permanent prohibition on future uses of groundwater at the site (for obvious reasons), DTSC makes a very interestingly worded statement in this Removal Completion Report letter.- bold
added for emphasis.

“During investigation activities, it was determined
that releases from the Chatham Yard do not appear to represent an environmental
concern to the Site of future occupants, as contaminate concentrations appear
to be naturally attenuating
The way it is worded it seems to mean that in some time in the
future when the natural attenuation is complete there won’t be an environmental
concern. Our concern is that DTSC’s opinion is based on future conditions, not current
conditions; ie, future occupants, attenuating.  
We have long-asked the agency when do they expect the attenuation to be complete (actions have been on-going for 20 years).  Here, they still don’t say when the process
of natural attenuation will be complete so that when the future occupants move
in they will be protected.  
So, does this mean that prior to issuing
occupancy permits the developer will need to do additional testing to
demonstrate that the process of natural attenuation is complete?