On December 11, 2005 several explosions took place in Buncefield Oil Storage Depot. It was the largest fire that Europe has seen in over 60 years. No concluding reports regarding the negative impact on the environment (especially on the ground water, caused by the intense fire-fighting measures and the air pollution, caused by the smoke) have yet been provided. The investigations of the accident are being performed by the Health and Safety Executive (HSE), in collaboration with the Environment Agency. The supervision committee for the investigations is the Major Incident Investigation Board (MIIB), consisting of independent experts, as well as HSE and EA employees. The MIIB has so far published three Progress Reports and one interim report.