Iron Mountain sustainability score: 40/100
Iron Mountain is mainly a records storage business: its records and information management segment brought in 76.7% of revenue in 2025, and data centres 11.6%. Most of the rest is asset lifecycle management and fine arts.
More about Iron Mountain
Iron Mountain Incorporated is a Delaware corporation whose roots go back to 1951, near Hudson, New York, and it has operated as a real estate investment trust since 2014. It had about 29,400 employees at 31 December 2025 and ~US$6.9B revenue in 2025.
Head office Portsmouth, United StatesStaff ~29,400 (year-end, 31 December 2025; about 11,700 US and 17,700 outside the US)Revenue ~US$6.9B (2025)Website ↗
Iron Mountain reported 1,188,141 tCO2e on market-based figures across Scopes 1, 2 and 3 in 2025, up every year from 874,798 t in 2022, with capital goods nearly tripling. It says 93% of its electricity is clean, and 74% of its total energy, resting on on-site solar of about 1.2%, direct contracts, certificates and virtual PPAs, with no split published. SBTi's list carries net zero by 2040 and a 54.6% Scope 1 and 2 cut by 2033; its near-term Scope 3 target is supplier engagement, at about 17% against 84.2% by 2028. Water withdrawals rose, with data covering 49% of floor area. No environmental fine or upheld regulatory action was found.
Iron Mountain scores 40/100 (Below expectations) on SINK's independent climate assessment, scored from public data only. Scores are free. Companies can never pay for anything about their own score. Last verified November 2026.
That places Iron Mountain joint 423rd of 994 companies scored, and joint 21st of 39 in Construction / Real Estate.
What is Iron Mountain doing well, and where does it fall short?
Strongest on Carbon Footprint: Operations and Targets & Commitments (8/10, 8/10). Weakest on Emissions Trajectory and Nature & Biodiversity Impact (0/10, 3/10).
Where Iron Mountain lost points
For each question that lost points, the evidence our public rubric looks for that we didn't find.
- Emissions from its own operations8/10No verified figures published with their method and a falling trend.
- Emissions from its supply chain7/10No full value-chain map or supplier engagement programme.
- Whether its emissions are falling0/10No evidence its emissions are falling, not even from energy bills or mileage.
- How clean its energy is4/10Less than half its energy shown to be renewable, or no transition plan.
- Its effect on nature3/10No assessment of its effect on nature, and no basic environmental policy.
- How it uses materials and handles waste5/10No measurable waste or recycling targets reported publicly.
- Its effect on water4/10No measured water footprint with reduction targets.
- Its climate targets8/10No validated long-term net zero target.
- How openly it reports8/10No mission-locked structure, such as B Corp certification.
A score changes when the evidence does. We use new published evidence at the next rescore. Anyone can send us new evidence, free. How to send it.
How is Iron Mountain's SINK score calculated?
Same ten questions for every company. No private weighting.
SINK = (0.3 × Base + 0.7 × Performance) × ScaleWhat evidence is Iron Mountain's score based on?
10 sources used in this assessment. All publicly available. Each row shows which of the ten questions it informed.
50% of them were published by Iron Mountain itself; the rest come from independent sources.
Scope 2, 2025: market-based 46,965 t, location-based 265,073 t. The score uses market-based.
“Total Scope 1 and Scope 2 emissions, market based 199,314 178,834 167,655 167,838”
“The installation comprises 17 stand-by backup generators to provide electrical power to the data centre”
“total Scope 1 and 2 emissions (market-based) rose from 2,496 in 2022 to 3,529 in 2025”
“Reduced Scope 1 and 2 greenhouse gas (GHG) emissions by 16% from 2022 to 2024.”
“renewable energy certificates (RECs) and virtual power purchase agreements”
“our 2017 commitment to 100% renewable power certificates”
“Iron Mountain Incorporated commits to reach net-zero greenhouse gas emissions across the value chain by 2040.”
“BSR used three climate scenarios developed by the Network for Greening the Financial System (NGFS).”
“it would impact 0.19 acres of palustrine forested wetlands and 280 feet of stream channel”
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How does Iron Mountain compare with other construction / real estate companies?
Where Iron Mountain sits among construction / real estate peers.
Among the 39 major construction / real estate brands we've scored, Iron Mountain is tied =21st of 39, with 4 others.
Who scores higher in Construction / Real Estate?
The 3 companies in the sector scoring nearest above Iron Mountain.
Taylor Wimpey has strong climate targets (SBTi-validated, net zero by 2045) and operational carbon reporting, but supply chain emissions remain 99% of its footprint with only modest reductions.
See the breakdown →British Land discloses comprehensively on carbon and energy, with SBTi-validated absolute Scope 1&2 targets and near-100% renewable procurement.
See the breakdown →Digital Realty reported 1,935,624 tCO2e across Scopes 1, 2 and 3 in 2025, down from 2,849,402 t in 2023, which its report puts mainly down to renewable procurement.
See the breakdown →Which companies moved this week, and why.
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