INVESTIGATORS WERE this week seeking to explain why a triangular window plunged 28 storeys from London's 30 St Mary Axe building - sometimes known as the Gherkin - on Monday morning.
The window fell 130m from the structure onto a plaza.
The area has been cordoned off while engineers inspect the building's 744 similar glass panes supplied by façade ecialist Schmidlin.
Building owner Swiss Re is investigating the incident.
A spokeswoman for 30 St Mary Axe said no date had been fixed for the investigation's completion.
The Health & Safety Executive is not involved in the probe, but a Corporation of London spokeswoman said the council was monitoring the investigation and that proper procedures were in place.
Bank Swiss Re occupies the lower 15 floors.
The Foster & Partners/Arup designed structure is 180m tall.
It opened in May last year and has scooped a string of awards.
No-one involved in the project would comment on the accident as NCE went to press.