Brian M. DelGhiaccio
Chief Financial Officer, Executive Vice President & Chief Transformation Officer at Republic Services
Thanks, Jon. Core price during the fourth quarter was 5.4%, which included open market pricing of 7% and restricted pricing of 2.9%. The components of core price included small container of 8.6%, large container of 5.6% and residential of 4.8%. Average yield was 3.4%, which represents a 20 basis point increase from our third quarter performance. In 2022, we expect average yield of approximately 3.4%. This is an increase of 50 basis points over our full year 2021 results. Fourth quarter volume increased 3.6%.
The components of volume included an increase in small container of 4.6%, an increase in large container of 3.7% and an increase in landfill of 6.7%. We expect organic volume growth in a range of 1.5% to 2% in 2022, which remains well above the long-term average. Moving on to recycling. Commodity prices were $218 per ton in the fourth quarter. This compares to $110 per ton in the prior year. Recycling processing and commodity sales contributed 110 basis points to internal growth during the fourth quarter. We are assuming $187 per ton for recycled commodities in 2022, which is consistent with the full year 2021 average. Next, turning to our environmental solutions business.
Fourth quarter environmental solutions revenue increased $65 million from the prior year. This was driven by organic growth from increased activity and the contribution from acquisitions. On a same-store basis, environmental solutions contributed 20 basis points to internal growth during the fourth quarter. Adjusted EBITDA margin for the fourth quarter was 28.1%. This compared to 29.9% in the prior year. Margin performance during the quarter was impacted by a 70 basis point headwind from higher incentive compensation expense.
We expect incentive compensation expense will return to target levels. Margin performance also included a 50 basis point dilutive impact from recent acquisitions, which included deal and transition costs. It should be noted that we pulled forward certain integration costs originally planned for 2022. The remaining impact to margin was primarily driven by a 50 basis point increase in risk management costs.
The current period includes a onetime true-up for an insurance captive that increased expense 20 basis points in the prior year included a 30 basis point favorable reduction in reserves, which did not repeat. We expect risk management expense in 2022 to be relatively flat with our full year 2021 performance. For reference purposes, fourth quarter margin performance at target levels of incentive compensation and excluding the onetime Committed to Serve payment would have been 29.4%. The remaining difference to prior year margin performance relates to the impact of recent acquisitions. SG&A during the fourth quarter was 10.6% of revenue.
This represents an increase of 60 basis points over the prior year, which was driven by higher incentive compensation accruals previously discussed. Full year 2021 EBITDA margin of 30% expanded 60 basis points compared to the prior year. This resulted from pricing levels in excess of cost inflation and effective cost management, which demonstrates our ability to gain operating leverage in the business. To put our operating leverage into context, we estimate wage inflation net of productivity was approximately 3%. Our average yield of 3.4% more than covered this level of cost inflation, which is why labor and maintenance were both down as a percentage of revenue for the fourth quarter and for the year. In 2022, we expect EBITDA margin will continue to improve and are targeting margin expansion of 30 to 40 basis points over our full year 2021 performance.
The components of expected margin expansion include pricing in excess of cost inflation adding 60 to 70 basis points and incentive compensation expense returning to target levels, adding 50 basis points, partially offset by acquisitions decreasing margin by 40 basis points and net fuel decreasing margin by 40 basis points. DD&A as a percentage of revenue was 11.2% for the year. We expect DD&A as a percentage of revenue of approximately 11.5% in 2022. Year-to-date, adjusted free cash flow was $1.52 billion and increased $279 million or 23% compared to the prior year. This was driven by EBITDA growth in the business and a reduction in interest expense resulting from refinancing debt.
Full year 2021 free cash flow conversion increased 350 basis points to 44.8%. We are targeting high 40% level conversion within the next couple of years. Total debt was $9.6 billion, and total liquidity was $2.8 billion. Our leverage ratio was 2.9 times. With respect to taxes, our combined tax rate and noncash charges from solar investments resulted in an equivalent tax impact of 24% during the fourth quarter.
This was in line with our expectations and resulted in a 26% equivalent tax impact for the year. We expect an equivalent tax impact of 26% in 2022 made up of an effective tax rate of 21% and approximately $120 million of noncash charges from solar investments. Let me now turn it back over to Jon.