An Asset Retirement Obligation (ARO) is a legal obligation associated with the retirement of a tangible long-lived asset in which the timing or method of settlement may be conditional on a future event, the occurrence of which may not be within the control of the entity burdened by the obligation. In the United States, ARO accounting is specified by Statement of Financial Accounting Standards (SFAS, or FAS) 143, which is Topic 410-20 in the Accounting Standards Codification published by the Financial Accounting Standards Board. Entities covered by International Financial Reporting Standards (IFRS) apply a standard called IAS 37 to AROs, where the AROs are called "provisions". ARO accounting is particularly significant for remediation work needed to restore a property, such as decontaminati