TWO engineers were killed when they were dragged into a conveyor belt as they repaired a machine which switched itself on, an inquest heard.

James Bibby, 25, and Thomas Elmer, 27, of Rossendale, died while working on a 150ft tall silo at a chipboard plant in Liverpool.

A jury heard the two were employed by Haslingden-based Metso to work as sub-contactors on a ‘dangerous’ piece of equipment which had powerful steel chain conveyors.

Experts from the Health and Safety Executive told how the power source to the machinery had been left on while the men worked in ‘a highly vulnerable position’ at the Sonae factory in Kirkby on December 7, 2010.

The incident was caused by a failure to isolate the machinery the two sub-contractors were working on, the inquest at Bootle Town Hall heard.

Coroner's officer Lynda Roberts told the jury: "It is believed the maintenance work was almost complete when the conveyor belt started up and both males were dragged into the machinery."

John Moutrie, a specialist mechanical inspector for the Health and Safety Executive (HSE), told the jury of four women and eight men that the ‘tragic incident’ occurred while the work was carried out ‘without the conveyor belt being isolated’.

He told how the computerised system sensed nearby silos were full, and activated the conveyor to the overflow silo where the men were working.

The chain conveyor remained on for over five minutes until a worker, realising it was not supposed to be operating and turned it off. The two men were then reported missing and later found in the overflow silo.

The nearest shut off button had been 35 metres and two ladders away from the workers.

He said: "This type of conveyor is dangerous. It is important that power is properly isolated before working on this machinery.

"The power was not isolated and remained on. Records show it was switched off for the first time that day five minutes after the incident.

"The isolation of power could be done very simply. Sonae issuing the permit would have needed to inspect this visually.

"The responsibility comes down to Sonae, not a company working there. They know the site and how it works. It's important that they double check workers have isolated power properly before work begins."

Mr Moutrie questioned the Sonae safety procedures and the ‘Permit to Work’ which he said outlined how a ‘permit issuer’, or staff member responsible for safety, should have checked that the machine was isolated.

He said the staff member in question was ‘apparently not trained’ and ‘may not have been competent to authorise the permit to work procedure’.

But Mr Moutrie also said that Mr Bibby and Mr Elmer should have checked their own machine and applied isolation ‘locks’ prior to starting work.

He said: "In my opinion if it's an outside contractor working on the site it's doubly important that it's inspected by the issuer."

The two men, from Waterfoot, were working on one of four silos, described as the overflow silo, which was used when the three other silos were full up.

The jury was told that prior to the incident both men were ‘fit and healthy’ and that toxicology tests later confirmed that no alcohol or drugs were found in their systems.

A post mortem found that both men died from multiple injuries.

The inquest, which is being presided over by Merseyside Coroner Christopher Sumner, is expected to continue for around three weeks and hear evidence from around 20 witnesses.