A 200m exclusion zone is still in place around the King's Place construction site as firefighters battle to cool highly flammable acetylene cylinders caught in the blaze.
And thousands of commuters face another day of travel chaos as the mainline station is set to remain shut for a further 24 hours. Tube lines have, however, reopened.
A London fire service spokesman said: 'Fires involving these types of cylinders cause major disruption in the capital on average once every month.
'Because of the risk of explosion, a 200m exclusion zone is set up every time these cylinders are involved in a fire.'
He added: 'A large number of people from the roads that fall within the exclusion zone have been evacuated.'
Dixon Jones told the AJ the fire will have some 'knock-on' effect on construction of the new building, but that it was still too early to say whether it would push back schedules.
'We are aware that the site is closed for another 24 hours. We were sending architects down there today for a meeting but that has now been cancelled,' said partner Edward Jones.
At least one person was rushed to hospital after fire swept through the development at the junction of Goods Way and York Way in King's Cross. Four fire engines and more than 20 firefighters rushed to the scene.
When it opens in 2008, King's Place will include 26,000m 2of office space, together with a 425-seat concert hall, an art gallery, restaurants and retail.
The design features a distinctive curved wave wrapping around to the Crinan Street elevation and a set-back upper storey.
It will bring together Guardian Newspapers' 1,400 London staff - currently scattered across seven London sites - and provide a new home for the London Sinfonietta orchestra.