LANGHAM, Sask. — Three or four people are usually killed every year in grain bin accidents, says Glen Blahey of the Canadian Agricultural Safety Association.
“We never know about close calls because they’re not reported.”
Most people who become entrapped in a grain bin do not survive. The number of entrapments is increasing in all areas of Canada, according to CASA. As the overall mortality numbers increase, a parallel trend is that more entrapments are occurring in large off-farm grain handling facilities.
“A study of grain entrapment cases in the States from 1964 to 2006 documented 82 percent of grain bin emergency calls ending up as (body) recovery calls, not rescues,” said Blahey.
The study, conducted by the American Society of Agricultural and Biological Engineers (ASABE), documented six rescuer deaths in that time period.
“In the cases where the victim was still alive when the rescue team arrived, only 10 percent turned out to be successful rescues,” he said.
“That means 90 percent of the victims who were still living when the team arrived died before they could be brought out alive. The cause is inappropriate rescue procedures and inadequate training.
“There’s nightmare stories about guys trapped in grain and somebody says they should just get a rope under his arms and hook it up to a tractor and pull. When you’re up to your armpits in grain, there’s more than 600 pounds of friction holding your body in the grain. When they pull on that rope, the first thing that happens is your shoulders pop out of their joints.”
And that’s just the first thing that happens to the human body.
To focus attention on this growing problem, Blahey has been on the road since early summer with CASA’s new grain bin rescue demonstration trailer. The mobile demonstration features a scaled down grain bin that replicates a typical accident in frightening detail. The re-enactment depicts many of the things that can go wrong when a rescue operation turns bad.
The good news is the demonstration also shows how a trained rescue team correctly extricates a victim engulfed in the grain. Although most people have heard about rescue tube equipment by now, Blahey said few people understand that a successful rescue is not just a matter of having your volunteer fire department rush out, shove a rescue tube around the victim and auger out the grain.
“If you are entrapped at the bottom of an inverted cone or funnel of grain, it might be up to your head by the time help arrives,” he said.
“If I rush into the bin with a neighbour to try save you, we’re trampling downward on the cone of grain, creating an avalanche. The grain will be over your head long before we can save you. The rescue process is more complicated than simply having the rescue tube and hand-held auger.”
Blahey said a common assumption is that you can just rip one side of the bin open to save the person inside. However, bins are engineered to hold a symmetrical column of grain. If there’s a lot of grain inside, ripping open a hole anywhere in the 360-degree wall can cause the whole bin to collapse on rescuers and bystanders.
One recommendation published by the ASABE involves rapidly removing grain by cutting holes, spaced equal distance apart, around the 360 degree perimeter of the wall. The engineers warn that too many openings or openings that are too big can jeopardize the structural integrity of the bin and cause a total collapse.
“If you make the holes too low, the grain comes rushing out, but it sucks the victim deeper down into the grain, where he can suffocate,” he said.
“If you try to torch a hole through the steel, you risk setting the grain on fire, especially in oilseed crops. Or you can trigger an explosion if there’s a lot of grain dust.”
Blahey recalled what once happened on a U.S. farm when a farmer was trapped in the grain. First responders arrived and began assessing the situation and forming their rescue plan.
“But the family and neighbours panicked,” he said.
“They thought the rescue team was taking too much time making their plan, so they started taking over the operation. They started torching holes in the bin. The fire department on the scene tried repeatedly to stop them, warning them there was a significant risk of an explosion.
“Every minute spent trying to calm the crowd was a minute wasted for the rescue team. The confrontation grew more intense. Finally, the state troopers had to be called in to keep the crowd from interfering with the rescue. The incident turned out to be a recovery. It points to the need to stay calm.”
ASABE said the average time for either a rescue or a body recovery is 3.3 hours from the time first responders arrive on the scene. In one incident, rescuers had to remove 267,000 bushels of soybeans from a 305,000 bu. bin. The victim had been missing two hours before rescuers were called. Again, the case ended as a body recovery.
Engineers began working with the concept of a grain rescue tube back in the early 1990s. Today, there are a number of commercially available grain rescue tubes on the market, all based on the same strategy.
The victim is nearly always at the centre of the cone. Two rescue workers wearing harnesses are lowered into the bin carrying the components of the rescue tube. There are typically up to eight, light-weight aluminum or poly sections which, when linked together, form a grain-proof case surrounding the victim.
A small hand-held auger driven by a cordless drill slowly sucks grain out of the protected area inside the rescue tube. As grain is drawn out, rescue workers push the tube deeper into the cone. Each time the walls of the tube are pushed down, the victim gains a bit more freedom of movement. Once the tube has been emptied, a harness is used to pull the victim up to safety. Prices for grain rescue tubes are in the range of US$2,500.
What to do if the unthinkable happens
In the event of a grain bin entrapment:
- Stop. Do not rush in an attempt to rescue the victim.
- Shut down and lock out all unloading equipment.
- Contact the first responder team.
- Turn on aeration and roof exhaust fans.
- Assemble everyone who is working on the farm at a predetermined location.
- Assess situation: stability of grain mass, condition of victim, air quality inside structure, availability of necessary rescue equipment and personnel best suited to carry out the rescue.
- Implement a situation-specific action plan.
Source: Journal of Agricultural Safety and Health
Editor’s note: Consideration should be given to the fact that the long-term study stretches back to 1964, long before grain rescue tubes had been invented. Also, the structural characteristics of today’s large bins are considerably different than in 1964.
- Based on 196 cases where the rescue technique used was known, the most effective method to extricate a victim from a grain mass was removing the grain from around the victim by cutting or punching holes in the side of the grain storage structure. This method was documented in 56 percent of cases.
- The potential for multiple victims due to catastrophic failure of a grain storage structure should be considered. Manufacturers of grain storage structures should conduct studies to predict the consequences associated with rapid removal of grain if those structures are breached during rescue operations. Warnings concerning potential structural failure if breached should be posted on the structure itself and included in the operator’s instructions.
- The second most frequently applied technique is constructing a grain retaining wall (rescue tube) around a partially entrapped victim. Grain inside the retaining wall is augered out, thereby freeing the victim. This method was used in 19 percent of those 196 cases.
- The use of powerful portable grain vacuums in documented rescue attempts is on the increase. This provides a previously unavailable resource for first responders. However, potential risks with this equipment were identified.
Source: ASABE report