The crumbling concrete that has closed hundreds of UK schools has also been found within two of Britain's biggest airports, it has been revealed.
London Heathrow and Gatwick both said that some of their buildings contain reinforced autoclaved aerated concrete and were being monitored.
Heathrow said it was taking'remedial steps' to mitigate any safety risk, while Gatwick said it was constantly monitoring affected areas. Both airports said passenger safety and operations would not be affected by the building materials.
T2 and T5 were both constructed after the 'bubbly concrete' was largely discontinued. The airport carried out work on Raac found in T3 last year, before the problems identified in school buildings this year forced many to close just before the start of the autumn term.
That has led to Raac becoming a political crisis, with the government facing urgent questions about the risk it poses in public buildings, such as hospitals, courts and prisons.
The recent concern led Heathrow to review the Raac management plans, but the airport has not changed its approach.
Gatwick would not disclose where its Raac was located, but it is believed to have been aware of its presence and have no indication of any risk.
A Heathrow spokeswoman said: No likelihood' of their buildings containing Raac, but airports were being double-checked as a precaution.
Raac is a greater risk in buildings that have not been properly managed, such as schools and hospitals in the public sector whose budgets have been reduced since 2010.
Chris Goodier, professor of construction engineering and materials at Loughborough University, said the presence of Raac was unlikely to affect airports, which have full-time maintenance teams: ve got money and they spend money because if they had to close a building it would cost them a lot.