Microsoft Fined Record $2.5 Million for Leesburg Data Center Air Pollution
Microsoft's data center in Leesburg, Virginia has been fined $2.5 million by the Department of Environmental Quality (DEQ) for violating air quality permits during a power outage last summer.
The facility switched to backup generators after a substation failure on June 27, 2025, and ran them for seven days. According to DEQ, Microsoft exceeded its permitted fuel throughput and emissions limits for nitrogen oxides, carbon monoxide, volatile organic compounds, and particulate matter during this time.
Microsoft submitted a response stating that their reported emission estimates were based on worst-case calculations and that they had determined a different methodology was more accurate. The company also claimed that an event like this would not recur due to historical reliability data from the electricity provider.
The DEQ and Microsoft debated over the method of calculating actual emissions between December 1, 2025, and July 28, 2026. During this time, Microsoft conducted stack testing at the data center to provide more accurate emission data.