Safety: Suspicions confirmed -- almost
January 26, 2009 By: Carl R. Metzgar, CSPAn unsigned editorial in Safety Sciences reminds loss-control practitioners: “Many interventions [read changes] have been used and are still in use to prevent injuries. However, in many cases it is unclear if an intervention [change] really works, and in some cases we cannot even be sure that an intervention does not actually do more harm than good.”
In the abstract, the use of training to reduce injuries is an active method of injury reduction. The miner is expected to apply what has been taught in training to reduce a risk. The modification of a tool to reduce risk is a passive method of injury reduction. The risk is reduced by the change to equipment. The miner doesn’t have to do anything.
Nail-gun research
“The relative value of training in preventing injuries has been and continues to be less than half that of switching to tools with the sequential trigger.”
This quote is from the conclusions section of an H.J. Lipscomb article in the American Journal of Industrial Medicine titled “Prevention of Traumatic Nail Gun Injuries in Apprentice Carpenters.”
It is not even remotely reasonable to overgeneralize this statement to all of the training and tools and equipment used in mining. This research report is about nail-gun injuries, and the conclusion applies to nail-gun injuries. However, used cautiously, there is a kernel of transferable utility from this specific nail-gun research. The point is that rigorous investigation teased out the utility of training and the utility of using a particular trigger on the nail gun. It is worth examining where the conclusion came from. The statement combines the usefulness and effectiveness of training and equipment changes.
Now, before you blow off nail-gun injuries as of no interest in mining, a quick call to the statistical branch of the Mine Safety and Health Administration in Denver revealed that from January 2000 through October 2009 there have been eight nail-gun injuries in mining. Three of them (38 percent) occurred in 2008. Not a big problem, but the tally proves a presence. Nail-gun spectaculars can be found by Googling “nail gun injuries.” The useful can be found in Lipscomb’s research.
The article cited was published in 2008, but the research started at least as early as 1999. Research is best when it is able to identify who is exposed to a hazard, how much exposure the workers have and how much the damage costs. Carpenter crews in domestic construction are small and widely dispersed. But Lipscomb was able to identify a good-sized manageable sample of carpenters and apprentices from which reliable information could be extracted to quantify the injury problem.
Injury breakdown
The results were 2.06 nail-gun injuries per 200,000 hours worked for the carpenters and 3.7 injuries per 200,000 man-hours for apprentice carpenters. That information was published in 2003.
By 2006 it was established that 78 percent of nail-gun injuries involved the contact trip mechanism and 19 percent of the injuries involved sequential triggers. Oh yes, the sequential but less-hazardous trigger required more nailing time. The extra nailing time wasof concern to the union carpenters who supported this research. In a project with journeymen carpenters, which was the subject of research, the extended extra time was less than 1 percent of the project time.
The researchers then worked to find the proportionate contribution of training and the use of the sequential trigger to risk reduction. Many different training delivery systems were used spread out over the four years of apprenticeship training. Both training (active) and trigger design (passive) loss-control methods contributed to reduction in injuries. The trigger design (passive), quantified in the conclusion quoted, was more effective, but the training was also a large contributor to progress.
The next step, quantifying management’s contribution to reduction of nail-gun injuries, will be infinitely more difficult.
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