v3.25.0.1
Landfill and Environmental Costs
 12 Months Ended
Dec. 31, 2024
Environmental Remediation Obligations [Abstract]  
Landfill and Environmental Costs LANDFILL AND ENVIRONMENTAL COSTS
As of December 31, 2024, we owned or operated 208 active landfills with total available disposal capacity estimated to be 5 billion in-place cubic yards. Additionally, we have post-closure responsibility for 125 closed landfills.
Accrued Landfill and Environmental Costs
A summary of our accrued landfill asset retirement obligations and environmental liabilities as of December 31 follows:
20242023
Landfill final capping, closure and post-closure liabilities$2,144 $1,937 
Environmental remediation447 485 
Total accrued landfill and environmental costs2,591 2,422 
Less: current portion(159)(141)
Long-term portion$2,432 $2,281 
Final Capping, Closure and Post-Closure Costs
The following table summarizes the activity in our asset retirement obligations, which includes liabilities for final capping, closure and post-closure, for the years ended December 31:
202420232022
Asset retirement obligations, beginning of year$1,937 $1,786 $1,507 
Non-cash additions61 61 60 
Acquisitions, net of divestitures and other adjustments4 12 175 
Asset retirement obligation adjustments91 41 20 
Payments(56)(61)(65)
Accretion expense107 98 89 
Asset retirement obligations, end of year2,144 1,937 1,786 
Less: Current portion(96)(72)(75)
Long-term portion$2,048 $1,865 $1,711 
We review annually, in the fourth quarter, and update as necessary, our estimates of asset retirement obligations. As a result, we increased amortization expense by $13 million, $5 million and $6 million for the years ended December 31, 2024, 2023 and 2022, respectively, primarily related to changes in estimates and assumptions concerning the anticipated waste flow, cost and timing of future final capping, closure and post-closure activities.
The expected future payments for final capping, closure and post-closure as of December 31, 2024 follows: 
2025$96 
2026108 
2027102 
202897 
2029112 
Thereafter7,758 
$8,273 
The estimated remaining final capping, closure and post-closure expenditures presented above are not inflated and not discounted and reflect the total estimated future payments for liabilities which include those incurred and recorded as of December 31, 2024 as well as liabilities yet to be incurred over the remaining life of our landfills.
Environmental Remediation Liabilities
We accrue for remediation costs when they become probable and can be reasonably estimated. There can sometimes be a range of reasonable estimates of the costs associated with remediation of a site. In these cases, we use the amount within the range that constitutes our best estimate. If no amount within the range appears to be a better estimate than any other, we use the amount that is at the low end of such range. It is reasonably possible that we will need to adjust the liabilities recorded for remediation to reflect the effects of new or additional information, to the extent such information impacts the costs, timing or
duration of the required actions. If we used the reasonably possible high ends of our ranges, our aggregate potential remediation liability as of December 31, 2024 would be approximately $273 million higher than the amounts recorded. Future changes in our estimates of the cost, timing or duration of the required actions could have a material adverse effect on our consolidated financial position, results of operations and cash flows.
The following table summarizes the activity in our environmental remediation liabilities for the years ended December 31:
202420232022
Environmental remediation liabilities, beginning of year$485 $487 $455 
Net additions charged to expense7 2 3 
Payments(62)(55)(55)
Accretion expense (non-cash interest expense)17 18 17 
Acquisitions, net of divestitures and other adjustments— 33 67 
Environmental remediation liabilities, end of year447 485 487 
Less: current portion(63)(69)(57)
Long-term portion$384 $416 $430 
The expected undiscounted future payments for remediation costs as of December 31, 2024 follows:
2025$63 
202659 
202746 
202846 
202928 
Thereafter256 
$498 
The following is a discussion of certain of our significant remediation matters:
Bridgeton Landfill. During the year ended December 31, 2024, we paid $12 million related to management and monitoring of the remediation area for our closed Bridgeton Landfill in Missouri. We continue to work with state and federal regulatory agencies on our remediation efforts. From time to time, this may require us to modify our future operating timeline and procedures, which could result in changes to our expected liability. As of December 31, 2024, the remediation liability recorded for this site was $62 million, of which approximately $11 million is expected to be paid during 2025.
West Lake Landfill Superfund Site. Our subsidiary Bridgeton Landfill, LLC is one of several currently designated Potentially Responsible Parties for the West Lake Landfill Superfund site (West Lake) in Missouri. On September 27, 2018, the United States Environmental Protection Agency (EPA) issued a Record of Decision Amendment for West Lake that includes a total undiscounted cost estimate of $229 million over a four to five year design and construction timeline. On March 11, 2019, the EPA issued special notice letters under the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) to Bridgeton Landfill, LLC and the other currently designated Potentially Responsible Parties to initiate negotiations to implement the remedy. On January 17, 2025, the EPA issued an Explanation of Significant Differences (ESD) applying the prior Record of Decision Amendment to an increased number of acres at the site found to contain radiologically-impacted material. The ESD includes a revised undiscounted cost estimate of $392 million. At this time we are neither able to predict the final design of that remedy, nor estimate how much of the future response costs of the site our subsidiary may agree or be required to pay. During any subsequent administrative proceedings or litigation, our subsidiary will vigorously contest liability for the costs of remediating radiologically-impacted materials generated on behalf of the federal government during the Manhattan Project and delivered to the site by an Atomic Energy Commission licensee and its subcontractor. However, subsequent events related to remedy design, divisibility, or allocation may require us to modify our expected remediation liability.