LAFARGE could face legal action after rogue workers at its Westbury plant deliberately signed off cement liable to cause 'concrete cancer' in buildings and roads as acceptable.

The company has admitted staff misreported the contents of batches of Portland cement between September 2002 and December 2004, but vowed the irregularities would not reoccur. The workers responsible have been sacked, and this week company bosses were playing down the situation, calling it a "minor technical issue".

The defective cement has higher than advertised

alkali levels, which can

lead to a damaging reaction known as concrete cancer, which causes structures

to expand and crack.

It was sold to several major ready-mixed concrete suppliers and has been used to build roads and houses across the west.

More than one mega-tonne of cement was affected and it can take anywhere between two and 15 years for alkali silica reactions (concrete cancer) to occur.

Lafarge says the problem will not cause structural failure, but customers such as RMC are understood to be considering legal action.

RMC spokesman Marit Meyer-Bell said: "We don't know what the costs are going to be but we hold Lafarge responsible."

A spokesman for Lafarge said: "We are a responsible manufacturer and stand by our product. Compensation is a longer-term issue, which is premature at this stage.

"Our focus is on working with our customers to support them in identifying any structures that could be at risk of developing a damaging alkali silica reaction and then having them assessed on a case-by-case basis."

Lafarge also confirmed "the individuals involved at Westbury no longer work for Lafarge".

Richard Baxter, of environmental pressure group The Air That We Breathe, said the blame should go further up.

He said: "The management at Lafarge are cynically trying to absolve themselves from responsibility by sacking other people. Lafarge's own Quality Policy document clearly states that the responsibility for the quality of their product goes all the way to the top."

Lafarge managing director Jean-Franois Sautin said: "We have apologised to our customers for the confusion and disruption caused and we are extremely grateful for their help and support at this time.

"To any worried homeowners, I would say that the threat to their home is minimal. This is a minor technical issue that should not give anyone cause for concern about the structural integrity of their property.

"However, we understand how confusion surrounding these issues can be upsetting and we invite anyone with a concern to call us for advice."

Anyone with concerns can contact the Lafarge Cement UK helpdesk on 0870 6090011.