Tobermore £160k fatality fine: lockout and interlock lessons for plant engineers
Reviewed by Joe Ashwell
First reported on The Construction Index
30 Second Briefing
Precast manufacturer Tobermore Concrete Products has been fined £160,000 at Londonderry Crown Court after production team leader Colin Thomas was fatally crushed on 26 April 2023 at the HESS1 block manufacturing line at its Lisnamuck Road plant. Thomas entered a fenced pit area for cleaning when a horizontal latch conveyor restarted, trapping him between the moving conveyor and fixed structure because the line had not been fully isolated and locked out. HSENI found unclear interlock zoning, absence of safety light sensors on HESS1 despite their use on similar lines, and inadequate supervision of cleaning and maintenance practices.
Technical Brief
- Failure mechanism involved entrapment between a powered horizontal latch conveyor and adjacent fixed steelwork in the pit.
- Interlocked perimeter fencing existed, but interlock zoning did not clearly indicate which conveyors were de-energised.
- HESS1 lacked safety light curtains or presence-sensing devices, despite these being installed on comparable block lines onsite.
- Investigation identified deficiencies in formal supervision of cleaning/maintenance, allowing routine work inside guarded areas without full isolation.
- HSENI stressed the need for “suitable and sufficient” task-specific risk assessments for cleaning and maintenance on automated lines.
- Lockout–tagout procedures were found inadequate, with no robust verification that all hazardous energy sources were isolated.
- For similar plants, retrofitting clearly zoned interlocks, light curtains and enforced LOTO is a key remediation pathway.
Our Take
Safety-tagged coverage in our database often centres on quarries and on-site construction incidents, so a fatality within a controlled precast environment like Tobermore Concrete Products’ HESS1 block manufacturing plant highlights that fixed-plant guarding and isolation procedures remain a weak point even in highly mechanised operations.
Northern Ireland appears relatively infrequently in the 41 Materials stories, which means this HSENI-led prosecution will likely be treated by UK precast and concrete operators as a reference case for how regional regulators expect risk assessments and machine interventions to be managed on automated production lines.
For operators running HESS-type or similar block production lines elsewhere in the United Kingdom, this incident in Tobermore is likely to trigger internal reviews of lock-out/tag-out, access control and interlock integrity, as insurers and corporate safety teams increasingly benchmark against high-profile fatalities rather than waiting for sector-wide guidance updates.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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