Hemel Hempstead building fire causes congestion 'near M1'
About 30 firefighters have been at a fire at an office block near the M1.
The blaze in the roof of the building in Breakspear Park, Breakspear Way, Hemel Hempstead broke out at about 09:10 BST, Hertfordshire Fire and Rescue Service said.
Five crews plus the aerial ladder attended and the fire was put out b 10:50.
Hertfordshire Police had warned of congestion in the area including at junction eight of the M1.
Highways England said the A414 westbound between the M1 and Maylands Avenue has reopened following the earlier closure.
A spokesman for Workman LLP, the managing agent for the building, said the fire started from the cooling tower works on the roof and there was "limited damage".
He said the building had been evacuated.
The building is within a mile of the explosion and fire at the Buncefield Oil Storage Depot in 2005, which was the biggest explosion in the UK since World War Two.