ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE

6 Months Ended

Jun. 30, 2021

Asset Retirement Obligation Disclosure [Abstract]

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE

ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSUREAccrued final capping, closure and post-closure costs include the current and non-current portion of costs associated with obligations for final capping, closure and post-closure of our landfills. We estimate our future final capping, closure and post-closure costs in order to determine the final capping, closure and post-closure expense per ton of waste placed into each landfill. The anticipated time frame for paying these costs varies based on the remaining useful life of each landfill as well as the duration of the post-closure monitoring period.

A summary of the changes to accrued final capping, closure and post-closure liabilities follows:


	Six Months Ended June 30,
	2021		2020
Beginning balance	$	82,533	$	71,927
Obligations incurred	2,319		1,764
Revision in estimates (1)	—		152
Accretion expense	3,676		3,204

Obligations settled (2)	(2,969)		(1,650)
Ending balance	$	85,559	$	75,397

(1)Relates to changes in estimated costs and timing of final capping, closure and post-closure activities at the Town of Southbridge, Massachusetts landfill. See Note 8, Commitments and Contingencies and Note 11, Other Items and Charges for further discussion.

(2)May include amounts that are being processed through accounts payable as a part of our disbursements cycle.