THE HIGHWAYS Agency could recall contractors to sites across the south of England to repair damage caused by concrete supplied by Lafarge's troubled Westbury plant.
Construction work on as many as 11 bridges and structures could have used the defective cement, which was supplied for over two years with dangerously high levels of alkali.
The agency fears that the schemes - many of which sit on busy holiday traffic routes - may be affected by spalling, crumbling or cracking.
The agency is staying tight-lipped over what steps could be taken but hauling down the affected bridges should concrete cancer develop has not been ruled out.
Contractors who originally built the structures may be held accountable because the schemes fall below six years of age.
One civils contractor said: 'If the work is relatively small then we may consider returning to appease the HA. If it runs into millions then we may not be so forthcoming. Its fair to say the agency would struggle to get any compensation from the supplier and may have to foot any bills itself.'
Improvements or replacement work would play havoc on routes including the M4/M5 Almondsbury interchange just north of Bristol.The junction is used for traffic heading to and from London and as a connection with the M5 for holiday destinations including Cornwall, Western-Super-Mare and the south of Wales.
Edmund King, executive director of the RAC Foundation, said: 'This could spell disaster.The junction is congested at the best of times and under any sort of work it becomes incredibly busy. It's a major junction which simply can't be closed for night work and of course as with any bridge or overpass work routes beneath are also affected so the problem is doubled.'
Also at risk on the M5 is the A303 New Solstice Park Junction. Built by Mowlem at a cost of £8 million, this is the main artery for traffic travelling to tourist favourite Stonehenge.
The agency has admitted it could take several years before the affects are fully known.
Sites under threat
A36 Skew Bridge Salisbury
A303 Solstice Park Amesbury S278 scheme
M5 J21-20 - Wick St Lawrence & Lampley Bow Bridges
M4/M5 Almondsbury Interchange - gantries
M4/A34 J13 Chieveley
M4 Shrub railway bridge, Swindon
A36 Limpley Stoke
A38 Kennford - Telegraph Hill Bridge
M27 Junctions 4-9 - gantries
M27 Junctions 9-12 - gantries
M5 Junction 31 Exminster