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Prison for construction contractor over fatal trench collapse

A building contractor has been jailed for six months after an employee was killed when an unshored excavation he was working in collapsed.

An example of an infilatration pipe

A company owned by William Ryan Evans was contracted to build a drainage field with infiltration pipes laid at the bottom of deep trenches, Swansea Magistrates’ Court was told. The pipes, which were 10 cm in diameter and made of lightweight, perforated plastic, aid the distribution of treated effluent through the field.

Evans employed two workers and subcontracted an excavator to undertake the work at Longstone Farm in Pembrokeshire. On 26 June 2012 Hywel Glyndwr Richards, 54, entered the trench to remove a clump of soil that had fallen into the trench when it collapsed. He was buried and died at the scene.

During its investigation, the Health and Safety Executive (HSE) found that the work had not been properly planned and the risk assessment was not suitable or sufficient. The workers were not correctly trained and equipment that could have prevented the trench collapsing had not been provided. 

Evans was sentenced at Swansea Crown Court on 11 April. He was found guilty of breaching Section 2(1) of the Health and Safety at Work Act and was given a six month custodial sentence.

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


Keeley Downey was the former assistant editor of IOSH Magazine. Previously she was editor of Biofuels International, Bioenergy Insight and Tank Cleaning Magazine


  • Where does the depth of 1.2m

    Permalink Submitted by IanC.. on 14 April 2016 - 08:30 am

    Where does the depth of 1.2m come from, surely the depth is dependent upon the ground nature and subject to risk assessment? Stating 1.2m could lead to a false perception that it’s safe to enter shallower excavations?

  • I quite agree with you Ian,

    Permalink Submitted by MarkN on 15 April 2016 - 06:56 am

    I quite agree with you Ian, different ground conditions present differing risk levels - i.e sand base, rock base. Each should be risk assessed specifically and where risk levels determine the excavation could be battered, terraced, trench boxes utilised or even sheet piled with struts installed. Working at height was in the past specified at specified at over 2m - when the regulations were introduced this was changes and similarly should the 1.2m for excavation work (which is also constituted as working at height (if working at ground level)

  • If my memory serves me right,

    Permalink Submitted by John Rayner on 16 April 2016 - 07:40 pm

    If my memory serves me right, 1.2m was the depth in the welfare regulations that were repealed in '96. However, the legacy is still often quoted & a lot of companies still use it in the trench support policies ...rather like the need to have a certificate to change a wheel on a disc-cutter.

  • Hello, I have corresponded

    Permalink Submitted by Louis_Wustemann on 18 April 2016 - 04:08 pm

    Hello, I have corresponded with HSE inspector Phil Nicolle and he says that while CDM requires any depth of excavation to be properly assessed and controlled:

    "It is, however, not unusual for Inspectors to use 1.0 - 1.2 m depth as a general indicator – ie rule of thumb that contractors understand and can work with in all but loose/granular and wet soils.   Many, and especially the smaller construction companies, still need a steer regarding the depth at which shoring or battering is inevitable when risk assessed, and the figure in the press release was used to assist these contractors.

    I would point your readers to the Construction Plant-hire Association guidance on Management of Shoring in Excavations which is the industry national guidance that HSE expects dutyholders to follow.  It is available as a free download at http://www.cpa.uk.net/shoring-technology-interest-group-stig-publications/.  The 2016 version has just been published to take account of CDM 2015.  Although the guidance stresses the need to assess all excavation work, the note at the end of Section 2.1 (bottom of page 8) deals with simplified policy as follows - NOTE: The policy adopted by an organisation can simplify the process. For example, a standing procedure that requires shoring before worker entry at depths exceeding 1m reduces the level of ground assessment required and simplifies the risk assessment process to that of selecting the type of support equipment required, dealing with other hazards and devising a matching system of work."

    Hope that helps.

    • if my memory serves me

      Permalink Submitted by John Norton-Doyle on 25 April 2016 - 12:57 pm

      if my memory serves me correctly, it was a long time that I was in a school of construction learning about waling, poling etc... but the configuration and application of support will also depend upon the type of ground (as well as surrounding "elements") . In such a case the reliance on a depth measurement may be overly simplistic and I think we all know its often the simple errors that lead to disaster. Like all good safety is not the maxim assess, assess, assess not matter what a "policy" says??


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