Five workers were injured last month when a fire broke out in a railway tunnel under construction in Spain. The incident happened in the 2.5km Vega del Ciego tunnel that will form part of the high-speed rail line between Madrid and the Asturias region.

The construction joint venture of Isolux-Corsan & Comsa (ICC) claimed that a spark in a sheet of waterproofing caused the fire that then burned the tunnel’s lining. ICC declined to comment further. Spanish police were on site investigating the fire as T&TI went to press.

All work has been halted until cleanup is completed. It is not known how long it will take.

The fire burned for nearly six hours, with more than 30 firefighters, mine rescue workers, ambulance workers and police involved in the control of the blaze. The five injured workers were treated for smoke inhalation and were all discharged the same day.

The fire burned part of the tunnel’s lining, a generator, rolls of unused waterproofing and several bits of machinery. The client, Spanish railway operator Adif’s technical personnel were on site, checking the tunnel and the machinery to assess the scope of damage caused by the fire. An Adif spokesman considered the damage of “little regard.”

Firefighters entered the tunnel from the southern portal and found the fire and heavy smoke about 500m in. Fire chief Jaime Martin said that his men could hardly see through the smoke and that breathing apparatus was necessary at all times. A fire hose stretching one mile was used to extinguish the blaze. Once the fire was extinguished workers ventilated the tunnel and cooled all hot spots hot spots detected by thermal imaging cameras.

The tunnel is part of the 4.9km subsections linking the towns of Campomanes and Pola de Lena.