Five workers have been killed in two separate tower crane accidents on opposite sides of the world in recent weeks.

On Sunday 21 May the boom and upper section of a luffing Wolff 320BF, owned by Hewden Tower Cranes, fell during erection and killed three men on a site at Canary Wharf in London, UK.

The previous month the boom of a Malaysian-built Favelle Favco TD 133 fell during a lift, killing two men.

The Wolff crane was the second of two cranes being assembled for the Canary Wharf Contractors joint venture which is building new offices for the HSBC bank. The first crane had been successfully erected. It is understood that the second was having its final top tower section put into place, with the climbing frame taking the weight of the top section when the whole upper works, including boom, slewing gear and cab, fell to the ground 120m below, across a road.

The three men killed were at the top of the crane when it fell. Further fatalities were avoided as the accident happened on a Sunday when this business district is at its quietest.

Investigations were continuing as Cranes Today went to press. MAN Wolffkran engineer Hans Schock, on site the following day, said that it was too soon to establish the cause of the accident.

There are echoes, however, of an accident in San Francisco in November 1989 when a tower crane also fell during climbing. That crane had been rotated just prior to failure, upsetting the balance of the crane on the climbing frame.

The Singapore accident happened on 11 April at the Pasir Panjang site of Japanese contractor Kumagai Gumi. According to press reports, the crane was bought in 1997 and had passed its annual safety check in May 1999. Preliminary evidence pointed to a broken pin and torn wire ropes that held up the boom of the crane.