The danger of a fuel vapour explosion at a petrol station is adding to the hazards of clearing a long, collapsed section of elevated highway from Luang Phaneg Road in Bangkok's Lat Krabang district.
About 100 metres of the elevated bypass, which is still under construction, collapsed on Monday evening, killing an engineer and a construction worker, injuring 12 other people, crushing cars on the road below and toppling power poles.
A concrete span about 100 metres long fell from a height of 20 metres onto Luang Phaeng Road between the Luang Phaeng branch of Lotus and Jorakay Noi police station about 6pm.
Police on Tuesday closed the inbound side of Luang Phaeng Road to all traffic.
Officials said it would take 3-4 days to clear away the debris - shattered concrete, reinforcing bars and steel supports.
City governor Chadchart Sittipunt said he would try to ensure Luang Phaeng Road is reopened to traffic in three days.
He said the elevated road was being built by a consortium of two qualified companies, Tharawan Construction and NPA Construction.
The governor said a crane known as a launcher and used to lift the section of elevated road had first tilted to one side, and then both fell onto Luang Phaeng Road. The investigation into why this happened was continuing, he said.
Deputy city clerk Narong Ruangsri said clearing of the road and its reopening to traffic was being given priority.
Mobile cranes were brought in to lift the fallen structures, which would be cut into smaller pieces for removal. Aerial drones were providing an overview of the site to aid planning and ensure safety.
The task was made more hazardous by limited space and the need for extreme caution because of a close-by petrol station, where vapour emissions had to be continuously monitored. A spark could trigger a fuel vapour explosion, he said.
The fallen span is part of an elevated road costing 1.6 billion baht being built between On Nut and Lat Krabang under contract to the Bangkok Metropolitan Administration (BMA).