Microsoft data center construction sparks debate over questionable reuse of surplus soil in Vihti

Surplus soil from Microsoft’s data center construction site in Vihti has been spread on local fields without environmental permits, despite ministry guidelines warning against the practice, reports Finnish broadcaster Yle.

The Vihti municipal construction and environment board has issued statements allowing landowners to use the “clean” excess soil for field improvements, even though some have received compensation from Microsoft—a factor that, under Finnish Environment Ministry guidelines, may classify the material as waste requiring permits.

According to the ministry, if financial compensation is paid for receiving surplus soil, the material should be treated as waste, subject to environmental permitting. The concern is that economic benefit, rather than genuine need, could become the primary motivation for accepting the soil.

Microsoft’s head of communications in Finland, Hennariikka Niinistö, confirmed to Yle that the Vihti data center project has generated significant amounts of excess topsoil and bedrock due to large-scale earthworks. While much of the soil has been transported to official reception sites, some has gone to smaller, individual locations—typically with compensation paid.

At least one Vihti landowner acknowledged receiving payment from Microsoft for taking the soil but claimed the funds were fully used for earthmoving work. Meanwhile, larger reuse projects in the area that would have required environmental impact assessments and permits have stalled.

The influx of soil transport has overwhelmed Vihti’s environmental oversight. “Workload has increased due to processing various reports and handling noise and other complaints related to the sites,” said Sari Brusila, Vihti’s environmental director.

Microsoft noted that its other Finnish data center projects in Espoo and Kirkkonummi have produced far less excess soil. Construction in Vihti is expected to continue until summer 2025, with soil transports now nearing completion.

The Helsinki region faces a broader shortage of soil disposal sites, and municipalities interpret ministry guidelines differently. Neighboring Lohja, for example, requires environmental permits if compensation is paid for surplus soil.