Grain bin entrapment fatality rate too high

URBANA, Ill. — The majority of grain bin entrapments occur in the Midwest.

“There have been over 1,100 grain entrapments since the 1960s,” said Salah Issa, assistant professor of agricultural and industrial safety and health at the University of Illinois.

“Surprisingly, 28% involved youth under 21 and 20% adults over 60,” said Issa during a presentation at CropFlix, the 2021 Crop Management Conference. “We tend to see this mostly in bins of corn, soybeans and wheat.”

Since the 1960s, Issa said, the fatality rate for grain bin entrapments is 67%.

“In the last five years the fatality rate is at 42%, so the efforts we’re doing to educate farmers about the dangers is working, but 42% is still really high,” Issa said.

“The cause of death for grain engulfments or entrapments is rarely reported,” he said. “But for these 33 cases, 64% of them died from asphyxiation.”

Researchers conducted several experiments to get a better idea of the impact of grain bin entrapments and extrications. The first experiment evaluated different grain types, the second experiment analyzed the forces that could injure a person’s spine and the third experiment evaluated the pressure of grain on a person’s body.

“We tested sunflower, oats, canola, wheat, soybeans, popcorn and corn at two different moisture contents,” Issa said. “We found that most grains were not significantly different.”

“We also did an experiment with a 180-pound mannequin that we pulled out at different angles from 15 to 75 degrees,” he said. “We wanted to get a better sense of how pulling at an angle impacts the total force when pulling out a victim and this becomes important because in a lot of cases you can’t pull someone straight up.”

Stayin’ Alive

When a person is entrapped in grain there are two different pressures involved.

“When the human body is trying to breathe, the chest is expanding and pushing against the grain,” Issa said. “The grain pushing against the surface is active pressure and when you’re pushing against the grain that’s passive pressure.”

“It’s not about the grain mass on the body,” he said. “It’s about your chest trying to push the grain mass out is what causes the shortness of breath.”

Grain temperature can also be a factor since it can remain 10 degrees cooler in a bin compared to the outside temperature, Issa said.

“A person in water at 4 degrees Celsius (39 degrees Fahrenheit) can survive for 30 to 90 minutes because water is 25 times more conductive than air,” he said. “Grain is seven to eight times more conductive than air, so we expect a person entrapped at 4 degrees Celsius to survive two to three times longer than in water.”

In addition, it is not solid grain in a bin.

“Grains tend to be 40% to 60% oxygen, so there could be oxygen to survive, but there are a lot more questions that need to be researched,” Issa said.

To evaluate the physiological factors of grain entrapments, Issa discussed a study with boa constrictors. The researchers thought the snakes kill people by attacking their chests so the victim can’t breathe.

“But when they did the study with mice they realized that’s not the case,” Issa said. “Boa constrictors apply pressure against the body to impact the blood flow and heart rate so the victim dies from a heart attack.”

Preventing Entrapments

Issa noted that 94% of grain entrapments are preventable.

“Operator error caused these entrapments,” he said. “The most important way to keep a person safe is use a lock out/tag out.”

There are not a lot of reports about harness use, Issa said, but if there is a report is it usually about misuse such as the safety line was too long.

“That’s doing nothing to protect you from getting entrapped,” he said.

In an entrapment situation, Issa said, the person should try to place his arms and hands in front of his mouth and chest.

“This is critical because in a lot of incidents they are inhaling grain and it also helps to reduce the pressure on your chest,” he said.