Richard, thanks for your comment. I withdraw the phrase “as is so often the case.” But I have to replace it with “as is sometimes the case.” I’ve investigated scores of fatal accidents where a system was designed, or redesigned, with little attention to safety. In some cases safety was considered with respect to normal operations, but not upsets.

 

But I understand that the claim requires evidence. So here’s a case in point: a small steel operation where an electric furnace was upgraded to increase its capacity. However, the intakes to the water cooling system were not relocated, so they were below the level of molten metal in the redesigned furnace. A year or so after the redesign, the furnace suffered a breakout (spill) and molten metal covered the intakes, which were not armored to withstand it. When molten metal covers water the result is an extremely powerful explosion, as the water instantly flashes to steam. A worker died.

 

Another example: a chemical plant making resorcinol. It’s an endothermic reaction, using a toluene feedstock, with heat supplied by a heat exchange coil circulating hot water. A bright young engineer decided the efficiency of the reaction would be increased if the water was replaced by molten sodium nitrate. He hadn’t considered the fact that the coil had been repaired with low temperature braising compounds, which melted due to the increased temperature and allowed the sodium nitrate to enter the vessel. It started to make organic nitrates, for example trinitrotoluene, with predictable results. Luckily, the explosion occurred in the wee hours of the morning, and the operator was taking a break on a balcony outside the room with the reactor vessel. He was blown off, fell 15 feet, two broken legs but lived. The really scary part was the unit making diethyl ether right next door. Shrapnel penetrated the thin walls, but missed the vessel. The plant sits in a narrow valley, with homes close by. You can imagine the effect of a vapor cloud of ether drifting over the sleeping families, looking for a source of ignition.

 

One more: a chemical plant using benzene as a process solvent in a reactor vessel. For safety and environmental reasons they had to phase it out. The engineers thought the easiest conversion was to n-hexane. But the chemicals are of course different, and the n-hexane tended to boil out of the vessel when the port was opened. The third time this happened, it found a source of ignition and a worker was burned to death.

 

These are not entirely the engineers’ fault. Management told them what they wanted, and safety wasn’t very high on the list. In the third case, management never bothered to ask for an investigation of the near-misses.

 

As to worker errors, they certainly exist. But I and my colleagues have investigated more than a thousand fatal and critical accidents since I signed on with the union. Workers are sometimes careless, distracted, and in a hurry to finish and get home. That’s human. But outright defiance of effective and properly communicated rules is rare. Most worker errors can be assigned to fatigue, conflicting or excessive job demands, poor training, faulty instrumentation, production pressure.  There’s a rich literature on human factors engineering backing that up.  

 

Incidentally, I was trained as an engineer (Cornell ’69) before I went on to public health. Safety was honored in the civil engineering classes; we began the very first freshman class with the Tacoma Narrows Bridge. But safety was mostly ignored elsewhere. Since graduating, I’ve sometimes been a guest lecturer at various schools. It’s astounding how many 3^rd and 4^th year engineering students have never had a human factors course, and don’t understand concepts like fail-safe design.

 

I have enormous respect for engineers; the profession links science with human needs. But engineers are like any other workers. They need good training, a good ethical code, a properly defined mission, good working conditions, and proper autonomy. And then they can do wonders.

 

Mike Wright

 

 

 

 

 

Your recent post included the phrase “. As is so often the case, the engineers hadn’t thought much about safety.” To which I take great exception. In my 45 years of engineering I have spent much more time and effort trying to get the workers to follow the safety requirements and use the safety equipment provided then I ever spent have to redesign something to make it safer. Yes that happened but it was rare. It is certainly true that a good hazard analysis and risk assessment will sometimes turn up something the designer missed which is why we do them but the bulk of the incidents I experienced in my career I n the energy industry showed that failing to use the equipment and follow the rules were the much more common root cause.

 

I can understand your background but I’d appreciate if you would please avoid inflammatory rhetoric like that in the future.

 

Richard Palluzi

PE, CSP

 

Pilot plant and laboratory consulting, safety, design,reviews, and training

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