Experts conducting a probe into last month's explosions at Buncefield oil depot have been told by the government to publish "as soon as possible".
Causes of the Buncefield depot fire are being investigated
It has been described as the "most wide-ranging" of its kind since the Potters Bar rail crash inquiry in 2002.
A series of blasts destroyed the depot in Hemel Hempstead, Hertfordshire, leading to the evacuation of homes and major damage to nearby buildings.
Lord Newton of Braintree is chairing the inquiry at the depot.
He is joined by Prof Dougal Drysdale, an authority in fire safety and Dr Peter Baxter, a medical expert.
Environment Agency and HSE staff are also be on the board.
Health and safety minister Anne McGuire said in a written statement: "The Health and Safety Commission's decision to establish an investigation board highlights the severity of the incident and the degree of concern for people living so close to the Buncefield site and to the local business community.
"It is determined to ensure the investigation is carried out thoroughly, objectively, transparently and concluded in a timely manner with its findings made public as soon as possible, subject to legal considerations."
In December, Bill Callaghan, chairman of the Health and Safety Commission, said the inquiry would be the most wide-ranging of its type since the 2002 Potters Bar investigation.
Among its terms of reference are to consider the factors leading up to the blaze, what ignited it and the root causes.
Mr Callaghan said it would also "make recommendations for future action to ensure the effective management and regulation of major action risk" at sites similar to Buncefield.