MSHA recently issued two fatality investigation reports for incidents at quarries involving haulage trucks. Both incidents, one in Missouri and the other in Pennsylvania, occurred in September 2013. The reports caught my attention in particular because both include this statement:

“Additionally, he was not wearing a seat belt and was ejected from the haul truck which contributed to the severity of his injuries.”

What do we know, or not know, about why some workers fail to wear their seatbelts?

First, here are a few details about the fatalities:

One involved a 1980 Caterpillar 773B haul truck. The driver, David A. Gully, 58, was traveling from the pit of a quarry up an unpaved haulage road with an 8 percent grade. The berm along the roadway consisted only of large boulders spaced 4-5 feet apart. When the truck maneuvered too far to the left, the berm was inadequate to prevent the vehicle from plummeting hundreds of feet over a highwall. (I’ll set aside my question about why the MSHA inspection, just a month earlier, did not identify the inadequate berm.)

The other involved a 1983 Jeep M35A2 cargo truck. Timothy Farr, 31, was using the truck to haul four 250-gallon water containers. He maneuvered the vehicle up the unpaved roadway, which had a 25 percent grade and three switchbacks. One of the containers fell off the truck, the load shifted, and the truck’s wheels lost traction. The vehicle moved backwards, the remaining water containers shifted and the truck overturned. The investigators found that the brakes on the truck had not been maintained and the containers had not been secured on the truck.

No one knows with certainty whether the workers would have survived these incidents had they been wearing their seatbelts. MSHA’s statement “contributed to the severity of his injuries” suggest that might be the case. So why don’t some workers wear their seatbelts?

A study by Kim and Yamashita, published in 2007 in Accident Analysis & Prevention identified two key reasons given by 791 commercial drivers in Hawaii for not consistently wearing a seatbelt: (1) they are uncomfortable, and (2) they are inconvenient for drivers who have to make frequent stops (e.g., to make deliveries.)

A study by Schlundt and colleagues examined the relationship between BMI and seatbelt use. They reported a decrease in seatbelt use as the BMI of drivers increased. They found this trend for all age groups, except among 16-24 year olds.

I few years back another fatality investigation report prepared by MSHA caught my attention.  It also involved a worker who did not wear his seatbelt. Robert C. Stewart, 28, was killed in September 2009 at ASARCO’s Ray (copper) mine in Gila County, Arizona. He was operating a 1997 Komatsu 830E dump truck when it struck a berm. When the truck overturned, Stewart fell from the cab and suffered fatal injuries. Like the two cases above, MSHA’s fatality investigation report indicated that failure to wear a seatbelt “contributed to the severity of his injuries.”  I wondered why Mr. Stewart was not wearing the seatbelt.  I considered reasons such as the following:

• Was the window on the cab open (that he fell from) because the air conditioning on the truck wasn’t working? MSHA’s report notes it was 80 degrees outside.
• The cab of the truck is about 20 feet off the ground. These monster trucks can have poor visibility. Without blind-spot cameras, did he need to remove his seatbelt in order to see out and around the truck and the roadway?

After near-miss incidents and work-related fatalities occur, investigators typically focus on the “cause” of the incident: Was the equipment not maintained? Were operating procedures inadequate? Had safety equipment been tampered?

But if investigators really want to get to the bottom of what happened, they also need to ask “but why?” But why was the equipment not maintained? But why has the safety equipment been tampered?

In the three fatal work-related injuries noted above, the victims were not wearing their seatbelts. MSHA concluded that this fact contributed to the severity of their injuries. But why weren’t they wearing them?

• If a worker is too large for the manufactured installed seatbelt, was a belt extender provided?
• If a worker finds the seatbelt is uncomfortable or slows them down from getting their deliveries made on time, could the worker and his employer figure out a way to remedy the situation so the seatbelt is worn dutifully?
• If the two-story high haulage truck has blind spots and the worker needs to unbuckle his seatbelt to see what’s around him, could visibility cameras be installed to rectify the problem?
• Is there simply a segment of the population who are stubborn and won’t wear a seatbelt no matter what intervention is tried?

When I read fatality investigation reports and I learn that the driver wasn’t wearing a seatbelt, my first reaction is often: “Really? No seatbelt?”  But I also know that we certainly should do more to find out why some workers don’t wear them. I’d like to see us asking that now, rather than wondering why after the worker is dead.