As we reported two weeks ago, 19-year-old Zach Dean Fox was working on Deanfoot Farm in Hawick, Scotland when the accident occurred on 1 August 2014. He was employed by H&M Farms (and had been for around one year) but was working as a contractor for Seamore Farming. At busy times of the year, these two separate companies contracted their employees to work on each other's farms.
The silos on Deanfoot farm stored various grains and seeds throughout the year. The silo in question was storing oilseed rape -- a black spherical seed about 1.5mm in diameter -- which Fox was discharging so the grain bin could be cleaned and prepared for oats. The bins were always cleaned out before a change of grain or seed to another.
The silo was open topped, rectangular in shape, and had been manufactured with a dividing wall in the middle to form two bins. Each bin was 2.95 m wide by 2.95 m deep by 4.82 m tall and the lower part of each side wall sloped towards the centre of the bin to create a 1.4 m long V-shaped funnel.
As the rapeseed was pouring out of the discharge point at the bottom of the silo, which comprised three diamond-shaped holes, it became blocked with straw and chaff that accumulated around the bottom and restricted the flow. Silo blockages are not uncommon, Health and Safety Executive (HSE) inspector Allison Aitken told IOSH Magazine, and workers always used the same method to clear them. This involved climbing inside the silo, which is classed as a confined space.
To access the vessel Fox climbed up the outside via the fixed ladder and inside using horizontal support bars and a rope. He then used a long metal pole to push the seeds through the discharge holes and clear the blockage. The solids started flowing freely again and Fox became immersed.
"A person standing on top of the grain during its discharge is at risk of being pulled down into the column of flowing seeds," Aitken said. "When someone becomes engulfed, releasing themselves, even with the help of someone else, is very difficult due to the pressure and the frictional forces exerted."
Fox entered the silo at around 8.30 am and was heard shouting by the partner of the business around 15 to 20 minutes later, according to Aitken. "Despite frantic efforts to save him, they weren't successful," she said. It is thought the bin, which had a storage capacity of 25 tonnes, was about a quarter full when the accident happened.
The HSE's information sheet, Managing confined spaces on farms, describes a confined space as "any place which is completely or partly enclosed" where there is a risk of "asphyxiation by free-flowing solids", among other hazards.
Seamore Farming failed to carry out a risk assessment for clearing blockages in the bins at Deanfoot Farm and failed to recognise the risk of asphyxiation from that task.
The HSE's investigation into the incident found the system of work in place to clear blockages in the grain bin was inherently and obviously unsafe because it could have been done from outside. Seamore Farming was fined £45,000 at Jedburgh Sheriff Court after it pleaded guilty to breaching Sections 3(1) of the Health and Safety at Work Act, which requires employers to protect those other than their employees, so far as is reasonably practicable.
There is a hierarchy of control, listed in the Confined Spaces Regulations, which employers must follow to manage risks associated with working in restricted areas such a grain silos, Aitken explained. Where possible, working in a confined space should be avoided by either modifying the space itself or doing the work outside. If it is not reasonably practicable to carry out the work outside of the confined space, a safe system of work must be followed. Appropriate arrangements should be made for rescue in an emergency.
"In the case of Seamore Farming, it was reasonably practicable for them to make minor modifications to the silos to avoid anyone having to enter to clear the blockages," Aitken said. Following the accident it implemented a safe system of work for clearing blockages in the grain bins by installing an access door that prevented workers climbing inside.
"This involved cutting an access hatch in the side of each silo at a low level which is covered with a door. The access hatch had both horizontal and vertical bars welded across it to prevent anyone from entering it," she continued. "When blockages occur the door can be removed and a long pole placed through the bars by someone standing outside the bin and directed down to the three diamond discharge holes to clear the blockages."