On 14 April 2010 James Sim, a 32-year-old sub-contractor for Balfour Beatty Utility Solutions Limited was working in a trench laying ductwork for an offshore windfarm being constructed by Heysham, Lancashire. The trench was dug to a depth of 2.4 metres without any shoring. The trench subsequently collapsed trapping Mr Sim causing fatal injuries.

The court heard how Balfour Beatty had failed to adequately risk assess the works or control the way in which the excavation took place. It pleaded guilty to a breach of Section 3(1) HSWA 1974, Regulation 31(1) of the Construction (Design and Management) Regulations 2007 and Regulation 3(1)(a) of the Management of Health and Safety at Work Regulations 1999.

Balfour Beatty was fined £2.6m and ordered to pay costs of £54,000.

In another trench collapse case, self-employed contractor William Ryan Evans was contracted to construct a drainage field comprising of infiltration pipes laid at the bottom of deep trenches.  He employed two workers and a subcontractor to undertake the work at Longstone Farm, in Pembrokeshire.

On 26 June 2012 Hywel Glyndwr Richards, aged 54, entered the trench to remove some soil when it collapsed, burying him and causing fatal injuries.

The HSE concluded that the work was not planned appropriately and the risk assessment was unsuitable and insufficient. There was inadequate training of the workers and unsuitable work equipment.

William Ryan Evans, of Carmarthenshire was found guilty at Swansea Crown Court of breaching Section 2 HSWA 1974 and given a six month custodial sentence.

HSE Inspector Phil Nicolle said: “This tragic incident could have been prevented by undertaking a suitable and sufficient assessment of the risks, providing the correct equipment or safe working methods to the workers and managing and monitoring the work to ensure it was done safely.”

He added: “Work in excavations needs to be properly planned, managed and monitored to ensure no one enters an excavation deeper than 1.2m without adequate controls in place to prevent a collapse.”

The two cases highlight the particular hazards involved in working with trenches, and the need to ensure that such work is properly planned and risk assessed in advance.