Furthermore, it is particularly difficult to substantiate the classification of environmental remediation costs as a component of nonoperating expenses. Because the events underlying the incurrence of the obligation relate to an entity's operations, remediation costs shall be charged against operations. Although charging the costs of remediating past environmental impacts against current operations may appear debatable because of the time between the contribution or transportation of waste materials containing hazardous substances to a site and the subsequent incurrence of remediation costs, environmental remediation-related expenses have become a regular cost of conducting economic activity. Accordingly, environmental remediation-related expenses shall be reported as a component of operating income in income statements that classify items as operating or nonoperating. Credits arising from recoveries of environmental losses from other parties shall be reflected in the same income statement line. Any earnings on assets that are reflected on the entity's financial statements and are earmarked for funding its environmental liabilities shall be reported as investment income.