Cement used to build roads and houses in 10 English counties could be contaminated and liable to crumbling, its producer said yesterday.
A spokesman for Lafarge Cement UK, which could face a large legal claim, said some employees at its plant in Westbury, Wiltshire, "deliberately misreported" the alkaline levels in bulk cement sold to customers over two years.
Its customers, ready-mix concrete suppliers, were told the alkaline content of the cement was lower than it was, Lafarge said. Structures may have been built which, in certain conditions, could begin to crack within two years.
Lafarge's managing director, Jean-Francois Sautin, said: "After we identified the problem we worked diligently on establishing the real make-up of cement for the period, so we could let our customers know and put changes in place to make sure the same thing cannot happen again." The misreporting of alkaline levels took place between September 2002 and last month.
The sub-standard cement is likely to have been used in houses, roads and bridges in Avon, Somerset, Berkshire, Dorset, Devon, Gloucestershire, Wiltshire, Hampshire, the Isle of Wight and Oxfordshire, said Martin Casey, of the British Cement Association.
Lafarge supplies several major companies, including Hanson, RMC and Tarmac.