The context of the CERCLA case law discussing "disposal" that I mentioned in the webinar occur when determining whether a person is a CERCLA PRP by virtue of owning or operating the site at the time of disposal.  For example, in Honeywell, the developer who owned the property in the late 70s, graded the site, and sold it in the early 80s was the owner at the time of disposal because he moved around contaminated material.

In the BFPP context, all disposal must occur prior to acquiring ownership of the property.  The danger for the prospective BFPP is that if development activities such as site grading occur at the property after ownership, it may jeopardize the ability to prove the defense.

Whether an area is a solid waste management unit (SWMU) or landfill subject to RCRA would be determined based on a different statutory and regulatory regime, and will probably not be impacted by the CERCLA case law discussing "disposal."  The analysis for determining whether a RCRA "hazardous substance" exists is a complicated one.  In addition, multiple guidance documents and cases have addressed when such waste is "generated," thus triggering RCRA requirements.  As you might expect, the regulations contain exceptions to the exceptions, and the regidity of many of the RCRA requirements makes it very unlikely in my opinion that the CERCLA case law will be directly applied in the RCRA context as suggested above. 

It is an interesting thought though, and we can't predict future.  It is all the more reason to take care when evaluating property development generally, and particularly demolition, which has numerous potential RCRA issues.