How serious is a transformer oil leak for operational safety?

Transformer oil leaks are a serious operational and safety concern. Loss of oil reduces cooling and dielectric insulation, increasing the risk of overheating, partial discharge, and internal arcing. Leaks also allow moisture and oxygen ingress, accelerating insulation aging. Environmentally, oil spills can contaminate soil and water, triggering regulatory actions. Fire risk increases if oil contacts hot surfaces. Even small leaks must be addressed promptly to avoid forced outages or catastrophic transformer failure.