As in all major incidents, the police established a "gold" command to bring together the emergency services and other key agencies. It is in Welwyn Garden City. In addition, the Government's eastern regional resilience team has provided a direct link with central Government, local authorities and voluntary agencies.

The initial focus was to secure the area and stop the blaze from spreading. About 100 police officers and 100 firefighters were at the scene yesterday, and about 150 firefighters from 12 different fire and rescue services are tackling the blaze today. They are succeeding in putting out fires in 10 of the 20 fuel tanks. About 275,000 litres of foam were used this morning, and more supplies are on the way. The fire services believe that they have enough foam to smother the fire and prevent it from starting again.

The scale of the incident was such that local resources were not sufficient, so the House will be grateful to fire brigades across the country that responded so quickly to calls for help. I also want to thank the people who are co-ordinating the response across the country so effectively.

I am pleased to tell the House that the high-volume pumping equipment, which was used so effectively in the Carlisle floods in January, has again proved vital. Just one of those high-volume pumps does the work of 18 traditional fire engines and it can pump water over a distance of some three miles. The new equipment was provided by my Department under the New Dimension programme for precisely those kinds of major emergencies.

The fire has had a number of wider consequences—in particular, health issues, the impact on fuel supplies and the provision of other public services. It has generated a large plume of smoke, which has spread widely. The plume is largely made up of carbon dioxide, carbon monoxide and hydrocarbons. As the fire comes under control and as the heat reduces, there may be an increase in smoke locally. While I am advised that the plume is not toxic, the smoke is certainly unpleasant and may affect people with lung conditions.

The Department of Health is working closely with the Environment Agency, the Health Protection Agency and the Met Office so that we can give up-to-date information about the plume and any implications for public health. Anyone concerned about the impact of the incident on their health should contact NHS Direct. Residents in the affected areas should stay in, close their windows and watch the news. As a precaution, a number of schools in the area have been closed today and employees of companies in the cordon have been advised not to go to work today.

The movement of the plume was unpredictable, so officials have also been in contact with the European Union to keep other countries updated. Prior to the fire service's assault on the fire today, there were detailed discussions with the Environment Agency to ensure that the foam and water cannot reach the drinking water supply.

The oil industry and the Department of Trade and Industry are working to overcome any impact that the incident may have on supplies of aviation fuel to Heathrow and Gatwick. A number of local services have also been affected and some precautionary measures have been taken. In the immediate aftermath of the explosion, some local people were evacuated from their homes to two rest centres provided by Dacorum district council, but only a few people took advantage of that.

The whole House will, I am sure, wish to pay tribute to the way in which the local council, voluntary agencies and the whole community responded to the emergency. I understand that a few people cannot return to their homes yet, but most are expected to do so within the next 24 hours.

Road transport was seriously disrupted yesterday as a result of the fire. The M1, M10 and local roads were all closed. I am pleased to be able to tell the House that the M1 has now reopened, although entry and exit at junctions 7 and 8 will be restricted in order to allow easier access for the emergency services.

As I said at the start of my statement, the response to the Hemel Hempstead explosion is a great tribute to all the emergency and other services involved and it is also a testament to the benefit of effective emergency planning. In the world in which we now live—with increased risks of both terrorism and accidents—multi-agency, cross-government contingency planning is vital. 

Day in, day out, this type of preparation takes place behind the scenes and away from the glare of the media, yet it is for events such as yesterday's that we plan.

I can tell the House that, only three months ago, the emergency services in Hertfordshire conducted a successful exercise, covering just such an eventuality as occurred yesterday. The speed and efficiency of their response is testament to their foresight. Through the Civil Contingencies Act 2004, we put in place the legislative framework that set the foundation for that sort of multi-agency planning. The Government's investment in the New Dimension programme has also provided the equipment that worked so successfully in Carlisle and now in Hemel Hempstead.

It is through the bravery, commitment and professionalism of our emergency services that we can respond so effectively to events such as this. Last night, I witnessed a group of firefighters who were about to enter the inferno. We admire the courage and abilities of those firefighters, who work hard and willingly for the safety of the community. The House will want to record its admiration for their courage and dedication in working on behalf of the community. Not only the firefighters but the police and the ambulance workers deserve our fulsome praise and admiration. I am sure that the House will join me in recording our thanks and gratitude for the courage and hard work of our emergency services.