Firefighters returned Monday to fighting an oil depot inferno that has spewed thick smoke as far away as France after stopping briefly over fears that one tank in the complex might contain highly volatile fuel.
The 150 firefighters withdrew at 3 p.m. (1500 GMT) after extinguishing flames in 12 of the 20 tanks that were initially ablaze, said Chief Fire Officer Roy Wilsher. Five hours later, his office said firefighters were again tackling the blaze.
The fuel in the tank had been identified as avtur, a type of aviation fuel that was not as volatile as had been feared, Wilsher's office said.
Authorities say they believe the explosion at the Buncefield depot 40 kilometers (25 miles) north of &to=http://english.pravda.ru/main/2003/02/10/43193.html' target=_blank>London was an accident but they will examine other possible causes, including terrorism.
The terminal stores 16 million liters (4.2 million U.S. gallons) of fuel and the fire has caused jitters on the global oil market and raised questions about safety at the nation's oil facilities.
"There is nothing to suggest that it is anything other than an accident, but we're keeping an open mind and when we get into the site we'll treat it as a ... scene which could be a crime. We'll be doing full forensics," said Chief Superintendent Jeremy Alford of Hertfordshire police. "We'd be remiss if we didn't."