Even after the third anniversary of the collapse of the World Trade Center in the New York, the causes of the disaster are still being examined and discussed.
Almost 40 years ago, in August 1968, a public inquiry into the collapse of part of Ronan Point in London concluded that a local gas explosion in one room had triggered an incident that affected the whole height of one corner of the building.
The block was found to be structurally vulnerable to a socalled 'domino' effect. It had been 'system-built' and the local incident had triggered a catastrophic event.
As a result new legislation was introduced in Britain in order to limit the structural damage that could be caused by a major local incident and buildings throughout the country were re-assessed and strengthened where necessary.
While many European countries quickly adopted similar building standards they were largely ignored in the USA for many years and thus the World Trade Center (built in 1972), did not comply with similar legislation. The centre was thus a 'vulnerable' building from the day it was first occupied.
Even today, this fact has never been acknowledged by the various US inquiries into the disaster.
David Evans, 46 Laytons Lane, Sunbury on Thames, Middlesex, TW16 6LR.