EPA had been trying to coordinate access with Respondent since July 2008 and for reasons not clear to EPA, Respondent would not consent to access to the Property so that EPA could complete its investigation; EPA issued an Unilateral Administrative Order for Access to the Property for EPA to complete its investigation; EPA must perform sampling work at the Property because there is a reasonable basis to believe that there is a release or threat of release of a hazardous substance at the Property.