Microsoft Ordered to Pay $2.5M for Leesburg Data Center Pollution

The Virginia Department of Environment Quality (DEQ) has mandated that Microsoft pay a $2.5 million civil penalty for exceeding air quality standards at its Leesburg data center. This penalty, cited by DEQ officials as the largest ever for a data center, stems from an incident in July 2025 when a catastrophic failure at a local electrical substation necessitated running 62 emergency engines for seven days. DEQ found that these operations surpassed permitted fuel and emissions limits.

According to DEQ spokesperson Irina Calos, the data center emitted 102 tons of nitrogen oxides and 11.6 tons of volatile organic compounds, and used 1.19 million gallons of fuel between October 2024 and October 2025, significantly exceeding its permitted limits of 94.67 tons of nitrogen oxides, 6.86 tons of organic volatile compounds, and 655,850 gallons of diesel fuel.

Microsoft, in October 2025, contested the reported emissions figures, claiming they were based on a "worst-case calculation methodology" and that a different approach would yield more accurate results. The company also expressed confidence that such an event would not recur, based on historical data from the electricity provider.

Of the total fine, $99,000 will be directed to the Virginia Environmental Emergency Response Fund, while the remaining $2.4 million is earmarked for the DEQ's Supplemental Environmental Project, which includes acquiring additional air quality monitoring equipment, a monitor station, and air quality sensors.