Section 312.23 - Interviews with past and present owners, operators, and occupants(a) Interviews with owners, operators, and occupants of the subject property must be conducted for the purposes of achieving the objectives and performance factors of § 312.20(e) and (f) .(b) The inquiry of the environmental professional must include interviewing the current owner and occupant of the subject property. If the property has multiple occupants, the inquiry of the environmental professional shall include interviewing major occupants, as well as those occupants likely to use, store, treat, handle or dispose of hazardous substances [and in the case of inquiries conducted for persons identified in § 312.1(b)(2) pollutants, contaminants, petroleum and petroleum products, and controlled substances (as defined in 21 U.S.C. 802 )], or those who have likely done so in the past.(c) The inquiry of the environmental professional also must include, to the extent necessary to achieve the objectives and performance factors of § 312.20(e) and (f) , interviewing one or more of the following persons:(1) Current and past facility managers with relevant knowledge of uses and physical characteristics of the property;(2) Past owners, occupants, or operators of the subject property; or(3) Employees of current and past occupants of the subject property.(d) In the case of inquiries conducted at "abandoned properties," as defined in § 312.10 , where there is evidence of potential unauthorized uses of the subject property or evidence of uncontrolled access to the subject property, the environmental professional's inquiry must include interviewing one or more (as necessary) owners or occupants of neighboring or nearby properties from which it appears possible to have observed uses of, or releases at, such abandoned properties for the purpose of gathering information necessary to achieve the objectives and performance factors of § 312.20(e) and (f) .