INVESTIGATORS believe the huge fire at Tilbury Power Station could have started on a conveyor belt.

The power station in Fort Road, which employees about 230 people, was out of action yesterday, and is likely to remain so for several days as firefighters continue their efforts to keep the smouldering fire under control.

It comes as the Environment Agency said it would investigate the cause of the fire at the plant and whether its operator had complied with the conditions of its environmental permit.

The blaze broke out in two biomass storage tanks – known as hoppers – at the power plant on Monday morning, but was brought under control by the late afternoon. More than 80 firefighters worked through the night to tackle the inferno using special foam, at what is the biggest biomass power station in Europe.

They also had to remove thousands of tonnes of wood pellets from the affected area.

RWE npower, operator of the power station, has launched an investigation, but initial reports suggested the fire could have broken out on a conveyor belt where woodchips are carried, before going into a vat to be burnt.

A spokesman said: “We have begun a full internal investigation to determine the cause of the incident and will be reviewing the extent of the damage to the station over the coming days.

“We just can’t speculate at the moment when production will begin again, but as soon as we can get in and assess the damage we will have a clear idea. But people should not be concerned there will be a power shortage.”

For around 40 minutes yesterday production resumed at the plant, but this was only to clear some of the clogged up hoppers and it was powered down soon afterwards.

Adam Eckley, Essex’s deputy chief fire officer, said his crews faced painstaking work overnight.

He said: “Operations overnight looked at moving the affected biomass out of those two bunkers away from the site, but it was frustratingly slow progress, unfortunately.

“It is expected it could take up to two days for the embers to be removed.”

At the height of the drama, more than 120 firefighters were involved in the operation while crowds of onlookers gathered along Tilbury and even Gravesend riversides to watch huge plumes of smoke rise hundreds of feet into the air above the station.

An Environment Agency spokesperson said the site’s environmental permit meant it had to have plans prepared for such emergencies, but would not comment any further as the cause of the fire is not yet known and its investigation has not begun.