I was recently involved in a tragic situation in which machine guarding failed not because the mechanical design was inadequate but because the human system around it fell victim to a well-known weakness. The case is currently embroiled in litigation, so I will refrain from naming names and will change a few minor details, but I think it holds a valuable message to keep top of mind.

We are creatures of habit and no matter what safety rules and policies we establish, employees can only be successful if safe behaviors become ingrained in their unconscious and automatic behavior.

What’s the root cause?

Stanis, a maintenance worker at a large warehouse, was troubleshooting a machine about the size of a two-ton forklift. He moved it off the shop floor, away from where anyone might access it by accident. He removed a guard that covered a sharp rotating blade to check the workings of the rotors underneath. The machine was turned off, and he had already released any stored potential energy.

Stanis worked on the machine for several hours, but could not figure out what was wrong. At the end of his shift, mentally and physically drained, he called it quits for the day. He placed the guard up against his workbench in the shop and went home. He was sure he would figure it out the next day.

But the next day, Stanis woke up with the flu. Going into work was out of the question. Not only would he be pretty useless, but he would infect the rest of his crew. So he called in sick.

The machine Stanis had been working on was pretty important, and the company was getting behind on several projects that needed it. So Jennifer, another maintenance worker on the warehouse team, figured she would take a shot at figuring out what was wrong.

She grabbed Stanis’ notes and saw that his best guess was that it was the blade rotors. She turned the machine on, heard the familiar hum of the engine, and walked around toward the back to see what the rotor was doing. Before she noticed that the blade guard had been removed, her hand collided with the blades and she lost three fingers.

Where would you assign the root cause of this incident?

Should Stanis have spent an hour before leaving to reattach the guard with the intention of spending another hour removing it again the next morning? Out of an eight-hour day, wasting two hours doesn’t seem very efficient.

Should he have tagged out the machine before going home, so it couldn’t be turned on, even though the machine was in the machine shop and no one would be in the danger zone at any time overnight?

Should the machine have been designed with a failsafe so it couldn’t be turned on with the guard removed, preventing anyone from troubleshooting failures in that area?

System solutions

None of these are perfect solutions, although all of them could have reduced the risk of Jennifer’s incident at least somewhat.

Are any of them mandated by OSHA regulations? OSHA 1910 Subpart O covers machine guarding. OSHA 1910.147 covers lockout-tagout. But it is easy for real-life situations to fall through the cracks of regulations. And compliance should not be our primary motivation anyway; it should be employee safety. They are the lifeblood (literally) of the organization.

How often are employees faced with situations that clearly were not considered when the rules were made? They try to figure out a way to balance the requirements of this exceptional situation, their productivity, their safety, and the company policies.

Let’s go back to Stanis and Jennifer. Stanis assumed he would be the one to work on the machine in the morning. Since he knew the guard was removed, no other action was necessary. Reattaching and then re-removing the guard seemed like a waste of time. The tagout policy didn’t seem to apply to this situation either. Waking up with the flu was the furthest thing from his mind. While Stanis couldn’t have predicted he would wake up with the flu, many other things could have gotten in the way. A flat tire on his commute to work, a more pressing emergency at the warehouse that required his immediate attention the next morning, or any number of things could have come up. He should have instinctively left the machine in a hazard-free state.

And what about Jennifer? Her attention was naturally focused on troubleshooting the rotors, not the presence of the guarding. But she also knew she was not the first person to tackle the machine’s problems. She should have instinctively inspected the machine before starting to work on it to get a safety situation awareness.

In both of these cases, it is not a failure of policy but rather a mismatch between the employee’s attention on the primary job at hand and a secondary and less salient safety issue. Attention is naturally focused on the primary task at hand, and we have evolved an exceptional ability to filter out the rest. The only way we can incorporate other aspects into a behavior is by integrating them as an unconscious part of the primary activity itself.

This is not achieved through policies, rules and regulations. It emerges as a natural result of habit formation, such as the kind described by BJ Fogg’s Behavioral Model (http://behaviormodel.org for more info) or the famous quote about how to get to Carnegie Hall — “Practice, practice, practice.”