Two busy St Albans roads remain closed while there are fears the M1 may be forced to close after a large pile of woodchip remains on fire at a recycling centre in Potters Crouch.
The A414 both ways between the A405 Park Street roundabout and M1 Junction 7 and the A4147 Hemel Hempstead Road, both ways between King Harry Lane and A414 Breakspear Way remain closed as a result of smoke from a fire at a wood recycling plant in Appspond Lane.
Firefighters have been at the scene since 1am on Sunday morning, after the wood material caught fire and initially firefighters left the recycling centre after a few hours of putting the fire out.
They were then called back at around 9am on Sunday morning after the fire flared up again. Crews from Hemel Hempstead, St Albans, Hitchin, Kings Langley, Redbourn, Ware, Berkhamsted, Welwyn Garden City, Stevenage, Rickmansworth, Borehamwood, Watford, Potters Bar, Bushey, Wheathampstead, Hatfield, Garston and Royston have attended, as well as the aerial ladder platform from Stevenage and high volume pump from Welwyn Garden City.
Helen Buckell, St Albans firefighter for white watch, said: "I attended the call on Sunday and initially it was smoking and the wood was smouldering away.
"Eventually the fire broke through it and we used fire monitors for fighting and tackling the blaze.
"It is quite a big fire in its dimensions and we are dealing with large stacks of wood, so it is going to take a while to put out."
The speed limit on the M1 is currently 40mph in both directions and a spokesman from the Highways Agency has said it will be forced to close the road if the wind changes due to safety.
Non-motorway traffic users are also being advised to plan ahead and leave extra time for their journeys.
The Hertfordshire Fire and Rescue Service is now working closely with the Environment Agency, St Albans District Council, Highways Agency and Hertfordshire County Council.
Fire crews from Watford, Wheathampstead, Redbourn, Hatfield and Royston are currently on the scene along with the incident support unit from Hitchin.
The St Albans & Harpenden Review has been told firefighters are expected to stay on the scene for another day and heavy congestion is expected in St Albans and Hemel Hempstead throughout the duration of the closures.
A diversion route is in place via the A414 St Albans Road, A414 Two Waters Way, A41 Watford Road, A41 Gadeside and A405 North Orbital Road. Lucy Hunt, 16, who lives in Claudian Place, St Albans, said she could see the flames from nearby her house and went to see what was happening with her father and sister.
Lucy, who goes to Oaklands College, said: "I have never seen anything like it before. I am sure it is going to get bigger.
"If you didn’t know there was a fire you would think it was snowing because there was so many flakes and ash in the sky.
"Cars on the M1 were slowing down to look at the orange flames and glow."
Diggers, used by the services, are currently being used to move the wood material, thought to be around 22,000 tons, so they can locate and fully extinguish the fire.