12. Asset Retirement Obligations (“ARO”) and Accrued Closure Costs

Accrued closure costs represent our estimated environmental liability to clean up our fixed-based regulated facilities as required by our permits, in the event of closure. During the nine months ended September 30, 2022, the Company recorded a total of $465,000 in additional estimated closure liabilities (within long-term liabilities) and ARO in connection with the footprint expansion at one of our facilities and an update to a processing enclosure area at another facility. Additionally, the Company recorded approximately $662,000 in additional estimated closure liabilities (within current liabilities) and ARO for our EWOC (Oak Ridge Environmental Waste Operations Center) facility. The ARO is reported as a component of “Net property and equipment” in the Consolidated Balance Sheets at September 30, 2022.