We also announced the pending divestiture of our 50% ownership in the flexible products and service business for outstanding value, solidified our net leverage position, and increased our profit expectations for fiscal 2022.
Mission 1, creating thriving communities.
Mission 3, protecting our future.
Global large plastic drums and IBC volumes grew by roughly 8% and 11% per day, respectively, versus the prior-year quarter.
Global steel drum volume fell by 4% per day versus the prior year due to customer supply chain and labor issues despite strong underlying demand.
Similar to quarter 4, the biggest volume shortfall was in APAC, reflective of our decision to implement strategic pricing actions and supply chain disruptions that negatively impacted our customers' operations.
The business' first quarter adjusted EBITDA rose by roughly $35 million due to higher sales, partially offset by higher raw material costs.
It possesses a very minimal cross-border exposure and contributes less than 3% to total company operating profit annually.
In January, we announced an agreement to divest our 50% ownership in FPS.
Although we have worked closely with our joint venture partner in the last 12 years, we evolve to have differing views on the future of this business.
The sale of our 50% stake in flexibles will generate net cash proceeds of approximately $123 million, subject to customary closing conditions.
Until we refine this further, you can assume FPS ballpark annual adjusted EBITDA contribution to be roughly $35 million.
Paper packaging's first quarter sales rose by roughly $129 million versus the prior year due to stronger volumes and higher published containerboard and boxboard prices.
Adjusted EBITDA rose by roughly $24 million versus the prior year due to higher sales, partially offset by higher raw material, transportation, and utility costs, including a significant $42 million drag from significantly higher OCC costs.
First quarter volumes in our CorrChoice [Inaudible] system were up roughly 0.5% per day versus the prior year.
First quarter [Inaudible] core volumes were up by 4.6% per day versus the prior year, with demand strong across almost all end markets.
First quarter adjusted EBITDA rose by $58 million year-over-year despite an OCC index headwind of $42 million and roughly $33 million of nonvolume-related transportation and manufacturing labor inflation.
Absolute SG&A dollars rose $17 million versus the prior-year quarter, mainly due to higher health, medical, and incentives costs, but fell 200 basis points on a percentage of sales basis.
Below the line, interest expense fell by $8 million versus the prior-year quarter, due primarily to refinancing our 2021 euro notes with a low rate bank debt.
We expect interest expense to fall further as we utilize proceeds from the flexes divestment on debt repayment and also benefit from having refinanced on Tuesday, our 6.5% 2027 senior notes with additional bank debt, utilizing a mix of floating and fixed rates below 3.5%.
Our first quarter non-GAAP tax rate was roughly 31% and significantly higher year-over-year due to increased pre-tax income, with a higher proportion of that income in the U.S., and less positive discrete items than the prior year.
Even with significantly higher tax expense, our first quarter adjusted Class A earnings per share was still more than double to $1.28 per share.
Finally, first quarter adjusted free cash flow was $19 million cash outflow and lower year-over-year, primarily due to higher capex-related maintenance and organic growth investments in IBCs, plastics, and specialty corrugated products.
Our core capital priorities remain unchanged: reinvest in the business to create value and support growth; return excess cash to shareholders via an attractive and growing dividend; and maintain a compliance leverage ratio between 2 times to 2.5 times.
We have overcome that headwind and increased the midpoint of our adjusted earnings per share guidance by $0.45 to $6.60 per share for fiscal '22, reflective of solid first quarter performance, announced paper price increases, and lower interest expense.
We now anticipate generating between $380 million and $440 million of adjusted free cash flow in fiscal '22.

Summary:
Even with significantly higher tax expense, our first quarter adjusted Class A earnings per share was still more than double to $1.28 per share.