COMMUNITY leaders were last night seeking assurances from a chemical company that an explosion was a one-off incident.

The blast that rocked Teesside has caused concern among residents and led to calls for the company at the centre of the drama to reveal what happened.

It is thought a fire involving mixed gases - including hydrogen, nitrogen and ammonia - started in a pipe at the Terra Nitrogen site shortly after midnight yesterday.

People living nearby told how the explosion rattled windows and set off car alarms. A boom and flame could be heard and seen 20 miles away.

Roads were sealed off around the scene and people were advised to keep doors and windows shut as a precaution while the plant was shut down.

Police said the incident, which was initially classed as a major emergency, was scaled down by about 3am and there were no off-site risks to the public.

Two people working at the site - the former ICI plant in Billingham, near Stockton - were treated for minor cuts and shock.

A joint investigation by the Health and Safety Executive and the Environment Agency was launched yesterday.

Last night, Stockton North MP Frank Cook demanded to be kept fully informed on the progress of the probe.

He said: "Like everyone else, my initial reaction is relief that the incident was dealt with and contained quickly and efficiently by the company and the emergency services - and that casualties were so few and so minor.

"Of course, the people of Billingham are used to having the chemical industry as their neighbour, but naturally they will be anxious to understand what exactly happened."

But people living near the plant last night told of being unaware of the dangers and spoke of fears of a repeat - or, even worse, something like the Buncefield oil storage depot explosion, in Hertfordshire, last year.

Lesley Nicholson, 55, from Roscoe Road, said: "I was really annoyed that the police or fire brigade didn't come and let people know what was happening."

Denis Hampson, head of Cleveland Emergency Planning Unit, said the usual procedure of warning people via local radio and informing them of what was happening had been carried out.

Carol Devlin, Terra Nitrogen (UK) Ltd managing director, said: "Terra recognises that the incident caused concern locally, but does not believe the event presented any danger to the public or would give rise to any public health issues."

Dr Stan Higgins, chief executive of the North East Process Industry Cluster, which represents more than 200 companies in the region, said: "The public can be assured that the industry takes safety extremely seriously and takes all the actions it can to keep the public and employees safe if an incident does occur."