The person in charge of the management office of Kerry Tc Warehouse 2, where the concrete piece fell off, was arrested yesterday. The slab sized about two by three meters fell on Wing Hau Street at about 10.34am, with the shattered fragments causing injuries to a male and female passersby's arms, waist and legs.

The duo - a 72-year-old man and 47-year-old woman, both surnamed Au Yeung - got hurt after sweeping the graves and were sent to the Princess Margaret Hospital for treatment. They remained conscious when being sent to the hospital by ambulance.

It is understood that police officers were carrying out crowd management measures in the area when the accident took place, as many people headed to the Tsuen Wan Chinese Permanent Cemetery as the Ching Ming Festival approaches.

The police cordoned off the road as the concrete pieces scattered along the area and people were guided to enter the cemetery through other openings.

The person in charge of the warehouse management office, a 53-year-old man surnamed Wong, was arrested for allowing objects to fall from the building and was taken in for investigation.

Retired Polytechnic University engineer Lo Kok-keung said the concrete pieces fell because of the rusting of the building's steel bars. This led to the concrete separating from the building's exterior walls.

The problem of aging buildings is inevitable and the SAR can only prevent such accidents through regular inspection and maintenance, he said, adding that the authorities should enhance inspections of private residential buildings.

"All buildings should be inspected in the same way because they all have the same kind of external wall," Lo said. "The walls of private buildings are not more durable compared to public ones."

He suggested that the government should require all owners' corporations to submit maintenance reports of buildings every year through legislation to maintain the safety of residents and preserve the structures.