SIX fire crews were called to an incident at the Petroplus refinery at Coryton at 4.51pm on Friday.

A vapour release occurred in a Naptha unit where steam was pumped back into a boiler which caused it to malfunction.

The unit was isolated and made safe by Petroplus on site crews and Essex Fire crews left the scene in their care at 5.23pm.

The malfunctioning boiler meant that production in the unit came to a halt and as a consequence of this a much bigger and smokier than normal flame was seen coming from the tower.

Essex Fire and Rescue's Assistant Divisional Officer Jim Jones said: "Water from steam got back into a boiler and effectively took it out of action. Because of this they had to vent more waste product and this is what caused the bigger than normal flame.

"The waste was not as clean as normal and this caused more smoke to be produced.

"We have been monitoring the situation but there is nothing for the public to worry about."

A Petroplus spokesperson said: "We've had some operational problems which have resulted in a large flare, this is part of normal safety procedures."

The incident happened almost a year to the day since a blast and fire rocked the Coryton plant. 2007 Fire at Coryton: Video - Click here