Police and fire crews were concerned over the possibility of explosive substances being used in the Brett Drive unit.

They put up an exclusion zone of hundreds of yards around the industrial estate and Ravenside Retail Park.

Police cars were stationed at the entrances and exits. The immediate danger passed when fire crews from Bexhill and Hastings extinguished the flames.

Firefighters and police were called to Brett Concrete Ltd at around 10.15pm following reports of smoke.

The fire had taken hold in an area of land let to another company to carry out coach maintenance.

Two vehicles were already ablaze by the time crews arrived.

Three appliances attended the scene, along with an aerial ladder platform.

Members of East Sussex Fire and Rescue assisted paramedics in treating members of staff at nearby Tesco for smoke inhalation.

The Tesco store was slightly damaged and was expected to re-open yesterday (Thursday) afternoon.

Sub officer Graham Fletcher said: "What happened was the air conditioning had sucked in some of the smoke from the fire and staff were taken aback by the fumes.

"We helped paramedics to give oxygen to the people who were affected. We treated eight members of staff in total for slight smoke inhalation."

A spokesman for Tesco said the staff were recovering well and not considered to be badly injured.

Crime scene investigators confirmed yesterday morning they are not treating the fire as suspicious.

Inspector James Scott, of Bexhill Police, said: "What I have been told is, on the balance of probabilities, the main seat of the fire was in a bus. We do know welding was going on in the bus shortly before the fire was reported."

Rob Richards, area general manager for Brett Concrete Ltd, said: "There is quite a lot of damage to one of the buildings in the corner of the site. We can't say how much it will cost. It is very early stages and we have been here giving the people who need it access to the site and making sure they have the space to do their jobs."

Nobody from Brett Concrete Ltd was hurt.