Willow Island Disaster 1978
Abstract
In 1978 the cooling tower under construction at Willow Island, West Virginia, collapsed supposedly due to concrete failure. The disaster has since been dubbed the worst construction accident in American history, with 51 workers falling to their deaths due to the collapse . In this paper, both the technical and human factors leading up to and causing the disaster will be explored in greater detail, along with how they link to the context of the construction. This will be expanded into an account of what’s happened as a result of the event, and a discussion of its aftermath.
Key Words: Construction; collapse; technical; human; causes; context; aftermath
Introduction
Allegheny Energy, Inc. (now FirstEnergy) was an electric utility company focussed in the Mid-Atlantic region at the time of the disaster, and were building the Pleasants Power Station situated at Willow Island . The OPEC oil embargo in 1973 had a huge effect on the stability of the global energy market, causing many energy companies to look closer to home for reliable energy sources. This, along with the rapidly increasing energy demand in America due to improving living standards (see figure 1), was pivotal in motivating companies such as Allegheny to set up more power stations more quickly.
Willow Island Power Station already had two units in place capable of a combined 213 megawatts of power, and Allegheny’s Pleasants Power Station has since expanded this to 1300 megawatts . The new Pleasants Power Station has two concrete cooling towers, and it was during the construction of this second tower that the disaster took place. A suspended scaffolding system was being used which could be fixed to the tower as it was being built, instead of utilising support from the ground. This meant that the scaffolding was relying on recently poured concrete to support itself, which was arguably the most consequential factor in the tower’s collapse as the concrete hadn’t been given adequate time to harden.
Although it is now considered the most deadly construction accident in American history, this tragic incident is sadly not unique among engineering disasters in that it could have been prevented with more regard for both personal and process safety. Personal safety may be loosely defined as minor but frequent, affecting ‘one individual worker at a time’, whereas process safety ‘may cause major accidents involving the release of dangerous materials, fires and explosions’ , and is less frequent but on a larger scale. As will be discussed later in the paper, these two types of safety are contrasting but can also often be interlinked, with multiple slips in personal safety leading to a chain of events that result in a much larger-scale process safety hazard. This follows through to the idea of corporate social responsibility, as it’s the companies who are ultimately responsible for the welfare of their employees. Safety, as an integral part of any engineering project, should then be at the forefront of every engineering firm’s concerns, not just the individual worker’s.
Analysis
The collapse of the second Willow Island cooling tower occurred just after 10am on 27th April 1978, and an investigation into the disaster began that same day with the arrival of a team from the Occupational Safety and Health Administration (OSHA). The OSHA investigators were supported by a team from the National Bureau of Standards (NBS), who conducted field and laboratory tests as well as analyses using mathematical models. Figure 2 shows the results of their chemical testing of the concrete, highlighting the fact that the concrete did not meet the American Society for Testing and Materials (ASTM) standards in terms of minimum silicon dioxide levels. Silicon dioxide nanoparticles have been proven to increase the compressive strength of concrete, particularly at the early age of hydration , so the lack of silicon dioxide would have been crucial in affecting the failure of the fresh concrete.
One of the physical testing results from the NBS is illustrated in figure 3, which shows how the compressive strength of the concrete against strain varies with time. One five-foot lift of concrete was being poured per day, and hydraulic jacks raised the scaffolding with the tower as it got taller . This meant that the workers were relying on 24 hour-old concrete, which didn’t yet have the level of compressive strength required. In addition, the outcome of the NBS mathematical analysis suggested that there wasn’t any individual component failure within the construction set up. Therefore, a combination of these findings led the OSHA and NBS investigators to identify ‘the imposition of construction loads … before the concrete of Lift 28 had gained adequate strength to support these loads’ as the most probable cause of the collapse . Tom Williams, a worker who was on-site at the time, supported this theory, telling the Pittsburgh Post-Gazette ‘The scaffolding was attached to green concrete, dammit. They only gave the concrete 24 hours to cure and they should have given at least 72 hours’ .
The aforementioned OSHA/NBS investigation went into great detail with regards to the most probable technical causes of the incident, but failed to acknowledge any potential human factors to the same effect. A separate study of the disaster was undertaken by United Engineers and Constructors Inc., which concluded that ‘key evidence suggested that the problems originated due to a lack of understanding of the scaffold system by the workers, and also due to its systematic misuse’ . This is relevant because the strength of the scaffolding system worked around complicated geometry, and moving the scaffolding every day would give ample opportunity for the necessary structures to be placed at slightly incorrect angles. Furthermore, there is evidence that ‘management and workers were loading concrete from different spots’ in order to save time, which if true would be detrimental to the strength of the system as a whole .
Several safety issues have also been brought to light via interviews with the workers. In the same interview with the Pittsburgh Post-Gazette, Tom Williams said that he ‘had safety meetings every Monday night … And we kept putting in recommendations and they kept ignoring them. We just knowed this was going to happen’. This clearly demonstrates the lack of good communication between management and the workers, very possibly causing the misuse of the scaffolding system. Moreover, there was only one access ladder to the scaffolding with which to escape by, and several bolts supposed to attach the scaffolding to the tower were missing . These may well all be signs of a rushed approach towards safety on behalf of both the managers and the workers, who might have been more concerned with finishing the job than they were about their own welfare. This is exacerbated by the fact that the contractors had been warned about the problems of the recently poured concrete and the single access ladder by an OSHA inspector prior to the collapse .
OSHA was able to fine the Willow Island contractors $85500 for a total of sixteen safety violations, with ten of them being wilful . The Governor’s Commission on Willow Island Report found that ‘there were no inspectors or supervisors of any kind on the job whose responsibility it was to check the work’, which was one example of a wilful safety violation . A lack of supervision means that there would have been ample chance of workers making unintentional errors, and in a complicated scaffolding design without much room for error, any small mistake could have the potential to compromise the entire construction.
Discussion
The need for a systematic, quantifiable approach to safety has since proven to be of paramount importance, especially as engineering projects continue to increase in magnitude and complexity . However, the rare and often unique nature of large-scale tragedies like Willow Island means there is very little concrete data on these momentous disasters as a whole. That being said, finding ways to simplify the many potential causes of a disaster is vital if lessons are to be learned, so future accidents can be better predicted and prevented. Defining the relationship between process and personal safety and applying it to specific case studies is one method of systematically breaking down both the technical and human causes of an accident. From there, specific hazards can be targeted and then resolved on both an industry-wide and on an individual level.
Post-accident reports such as the one carried out on Willow Island by the NBS are often able to pinpoint a specific technical cause of the incident due to a lack of process safety, such as continually using wet concrete to support the scaffolding. However, identifying a chain of smaller but more frequent incidences of personal safety breaches leading up to the disaster is arguably just as important. The idea of the association between personal safety and process safety stems from the Heinrich principle, which proposes that for every major, life-threatening incident, you have several hundred smaller breaches of safety leading up to it. The point is that if these smaller personal safety issues can be prevented, these larger process safety hazards should be much less likely to occur .
While a single worker setting up their scaffolding at a slightly incorrect angle may not seem particularly consequential at first, if this happens on multiple occasions then the problem can amass and have a serious impact on the whole project. At the time of the Willow Island disaster an official statement was released by the area director for OSHA which supports this theory:
‘There were redundant features here that, if they had corrected them, this wouldn’t have happened… But when you put all of these things together all on the same day at the same time, this is what happened’ .
Moreover, identifying smaller and more specific safety breaches is commonly how new rules and regulations are brought into action. For example, as of 1988 concrete must be tested before forms and shoring are removed, and on-site inspections of forms and shoring were also mandated. In addition, partially constructed structures now cannot be loaded without certification from someone trained in structural design .
Although they are clearly linked, it’s also important to acknowledge that the difference in scale between personal and process safety means that they diverge from each other as well. Ensuring that all the workers at Willow Island wore safety helmets is an example of a personal safety measure that would not have impacted the major process safety issue of the wet concrete at all. However, making good personal safety commonplace is about holistically creating a positive safety culture. If the Willow Island contractors had taken safety seriously enough to give all of their workers specifications and supervisors to work with, then it’s unlikely that they would have forgotten to check whether the concrete was hard enough for them to continue building the cooling tower. It’s easier to make a habit out of good process safety if good personal safety is already prevalent.
It’s widely believed that engineering is about compromise, such as increasing cost to improve quality. The dangerous nature of many engineering projects, though, means that safety is something that can never be compromised. It’s up to engineering firms to take social responsibility by caring for their workers enough to regularly enforce safety measures, as they would enforce quality control or meeting deadlines. Providing formal training programs for workers, issuing correct PPE and adhering to industry-approved standards are all ways in which engineering corporations are taking this social responsibility with regards to safety in their hands.
Conclusion
In summary, on the 27th April 1978 a cooling tower in West Virginia collapsed as the Willow Island Power Station was being expanded into the Pleasants Power Station. The collapse is now known has the deadliest construction accident in American history, killing 51 workers who were on the scaffolding at the time. There were multiple likely causes of the collapse, with the elaborate scaffolding system and the use of concrete before it had properly hardened being the most conceivable. As a result, the Willow Island contractors were fined $85000 and cited with sixteen safety violations. Since then, due to accidents such as at Willow Island, new safety rules and regulations have been brought in such as those concerning the loading of partially constructed structures.
In my opinion, the fact that OSHA could cite the Willow Island contractors with any wilful safety violations at all speaks volumes about the attitudes of the Willow Island contractors towards safety regulations. It is promising, though, that safety requirements have adapted and progressed since Willow Island, and will carry on doing so in the future as the engineering industry continues to evolve. Analysing hazards in terms of personal and process safety appears to be very useful in identifying missing risk control measures and ways in which they might influence each other. This is one method among many, and is a step in the right direction towards being able to completely and systematically evaluate engineering projects, bringing the associated health risks nearer and nearer to zero. To conclude, I think that the fact that America hasn’t had such a deadly construction accident in all the years since 1978 is proof that the engineering industry is learning from past mistakes, and is growing into a safer and more effective place to work as a result. With better safety, we can be more productive and consequently bring more innovation to society.
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