The 2002 Brownfields Amendments to CERCLA created or clarified three related defenses for parties who did not cause contamination but have some connection to a contaminated property. The bona fide prospective purchaser defense protects a party who acquires property with knowledge of existing contamination, provided it conducted all appropriate inquiries before purchase and meets ongoing obligations afterward. The innocent landowner defense covers a party who had no reason to know of contamination at acquisition despite appropriate diligence. The contiguous property owner defense covers a party whose land was contaminated solely by a source on adjacent property.

Each defense requires satisfying an all appropriate inquiries standard before acquisition — typically a Phase I environmental site assessment conducted to the applicable federal standard — and requires the party to take reasonable steps after acquisition, including preventing further releases, controlling exposure, and cooperating with any ongoing or future response action. Failing to satisfy these continuing obligations can forfeit the protection even where the pre-acquisition diligence was adequate.

State voluntary cleanup programs frequently offer parallel liability protection and often coordinate with federal brownfield protections to encourage redevelopment of contaminated sites. In a Juricratic simulation, a prospective purchaser can dial the strength of its Phase I diligence record and post-acquisition compliance against the likelihood a later claimant successfully challenges the defense, useful for rehearsing acquisition risk before committing to a brownfield redevelopment deal.

Brownfield liability protection is invoked defensively when a current owner who purchased contaminated property is later named in a cost recovery or contribution action, with the litigation typically turning on the adequacy of the pre-acquisition environmental assessment and whether the owner met its continuing obligations after closing.