A man was taken to hospital after being hit by falling masonry "over a foot long" in East Street, Derby.
Police sealed off the area after receiving calls from the public at about 11.45am on Thursday about concrete falling on to the pedestrianised pavement below.
Poundland and BetFred were evacuated and a city council building surveyor was on the scene along with police and ambulance services.
An elderly man was hit on the shoulder by the debris and taken to hospital with grazing.
Balder Singh, 67, of Peacock Grove, Littleover, was in Derbyshire Building Society at the time and said everyone was told to stay inside for an hour.
He said: "I saw the man who was hit. I'd say he was inches from death. We were probably three minutes from walking under it. We are incredibly lucky and so was the man."
Another eye witness, Carolos Terrazas, said he was walking along East Street when the masonry fell.
"I was so shocked, it fell just a few inches in front of me," said Mr Terrazas, of Charwood Street, Derby.
Staff at the Co-operative Bank were also told to stay inside and were only allowed outside at 12.20pm.
Councillor Asaf Afzal, cabinet member for planning, environment and public protection at Derby City Council said keeping people in Derby safe was the number one concern.
He said: "As soon as our Building Consultancy team became aware that there was a public safety issue on East Street, they went to East Street and worked with the police to close off a section of the road.
"The team then fenced off the danger area around the fallen masonry, to allow the street to be opened to pedestrians.
"This fencing was put in place as quickly as possible in order to reduce the impact on customers and businesses.
"The Co-Operative still owns the building from which the masonry fell.
"A representative from the Co-operative has visited the site today and they will start erecting scaffolding tomorrow to enable investigations to be carried out on the stability of the building's façade."DID YOU SEE WHAT HAPPENED? If you witnessed the incident or took pictures or video please e-mail newsdesk@derbytelegraph.co.uk
