INCIDENT INVESTIGATION

Bird’s Domino Theory

Frank Bird updated Heinrich’s theory of Domino sequence to explain situations that lead to injury in a chronological order of five dominoes namely lack control by the management, underlying causes, immediate causes, accident, and injury. The first domino, lack of scrutiny, is the responsibility of the management. This domino entails accident investigation, job analysis, and personal communication, measuring performance using standards for the work activity and correcting performance by improving existing standards. The rules may fail in cases where there are insufficient measures and follow-up. In the case where the garbage truck hit the pedestrian overpass, the vehicle had undergone routine preventive inspections allowed to operate. However, noise and vibration tests were taken in the street behind the employer’s yard and not a public highway.

The noise and vibration levels in the testing phase were slightly different from the actual conditions of the incident on a public road. In the pipe blow off the case, there was no evidence of supervision of workers that were employed by the company. More so, there was no copy of safe work procedures on site or in the CO₂ operator manual. The work process in the plant is unclear because as much as they stipulate that the CO₂ operator should slowly open the product valve to release gas within 300 feet of the direction of the valve, workplace procedures do not indicate the position in which the CO₂ operator should stand (Friend & Kohn, 2007).

The second domino, primary causes, involves both personal and job factors. Personal factors are improper motivation, physical or mental problems, or lack of knowledge. The garbage truck was manufactured without an audible or visual alarm that would have warned the driver that the trash box was in an elevated position. Job factors entail low purchasing standards and work standards, and abnormal usage. For example, the garbage truck driver was probably tired from working overtime, which reduced his level of concentration while driving the vehicle. Another example from the pipe blow off case was that the elbows and connecting flanges of pipe assembly were SKD 80 thick as required but the straight pipe that connected the hose assembly was SKD 40 and therefore could not take the pressure (Hoyos & Zimolong, 2012). Fundamental factors are the source of substantial acts and failure to identify these factors allows the second domino to fall. [“Write my essay for me?” Get help here.]

Immediate causes are substandard conditions that serve as indicators of underlying problems that can cause the third domino to fall. Once they are identified, immediate causes should be classified and removed using appropriate measures. In the case of the garbage truck, the driver unintentionally activated the TIP switch while driving while he thought that he was enabling the DOOR ON switch. The same manufacturer developed the control panels of the trucks, but there were variations in they were positioned. In the pipes blow off situation, repositioning of the tube assembly might have caused threads on the straight piece of pipe to loosen where it was connected to the outlet.

The incident or accident phase entails outcome of unsafe conditions and acts. The garbage truck incident occurred when the truck collided with the pedestrian overpass. In the blow off the incident, the accident took place when the CO₂ operator opened the discharge valve to release excess CO₂. The pressure of the venting gas unthreaded the pipe assembly, which spun clockwise and struck the CO₂ operator (Stranks, 2016). The accident phase, also known as contact stage, involves utilization of countermeasures such as deflection, surface modification, segregation, deflection, barricading, shielding, or protection.

The injury or loss phase includes systemic effects from the work activity exposure or traumatic injury. The seriousness of injuries that involve physical harm or accidents can be played down by appropriate reparative action and salvage in the case of assets damage (Hosseinian & Torghabeh, 2012). The overpass rested on the cab of the truck causing fatal crushing injuries to the driver where his arms were entangled in the east guardrails. The pipe blow off incident also resulted in fatal injuries to the CO₂ operator.

Causal Factor Analysis
Garbage truck incident
In the garbage truck incident, the design of the overpass, road and vehicle conditions at the time of the incident were not considered as causal factors. However, the design of the control panel, the possibility of unintentional error in activating the TIP switch and lack of a feedback mechanism were the primary causal factors for the incident. [Click Essay Writer to order your essay]

1. Non-uniformity in the design of the control panels

The driver may have elevated the garbage box because of an unintended error. The driver pressed the TIP switch, which raised the litter box instead of pressing TOP DOOR switch to open. Unintentional errors are caused by lack of standardization of the interface between a human being and the machine that he is operating (Stranks, 2016). The driver in the accident drove at least three different trucks in a week whose control panels were similar but had significant differences in their basic control functions. Unlike the driver’s previous vehicles, the truck had a TIP switch, which was identical to the REAR DOOR and TOP DOOR switches. Therefore, the accident may have incurred as the driver was reaching for the TOP DOOR switch but accidentally activated the TIP switch instead which lifted the garbage box.

2. Lack of warning devices

The ANSI standard required that the control panel of the truck had either a visual or audible alarm to warn the driver if the garbage box became elevated. However, the manufacturer of the truck did not incorporate an alarm or visual signs in the control panel, and the company owner did not reinforce these features in the truck as required by ANSI.

3. Overtime shifts

The garbage truck incident occurred at the end of the workday when the driver was on an overtime shift, which implies that the driver may have been exhausted. Company policy required the driver follow a different route and truck from the usual. The driver did not have a swamper, and he was driving a truck that he had occasionally used. Tiredness and non-routine were factors that might have influenced him to raise the box unintentionally.

Corrective Mechanisms
To prevent similar incidents, the employer issued a critical incident alert to inform the staff of the details of the accident and remind them to follow procedures regarding vehicle clearance. Secondly, the employer retrofitted the TIP function with an audible alarm to warn the driver if the garbage box elevates.
Pipes blow-off incident
The direct causal factors of the pipe blow-off event where the configuration of the venting pipe assembly and the high pressure of the gas being vented. Underlying factors include lack of supervision and inadequate safe work procedures.

 

1. Venting pipe assembly

The CO₂ operator inappropriately vented CO₂ gas from a queen by using a vent pipe assembly made from onsite components. When the pipe assembly unthreaded at the outlet, the pipe assembly spun clockwise and struck the CO₂ operator.

2. Pressure of the gas being vented

Pressure from the CO₂ gas where it impacted on the pipe assembly caused it spin off the thread mount of the outlet.

3. Lack of supervision

Failure to provide enough supervision led to a scenario where the assembly plant workers were left to lead themselves and invent solutions to the problems they encountered as they worked.

4. Inadequate safe work procedures

Work procedures require that there is no object within 300 feet of the direction of the discharge valve was facing before venting CO2 in the atmosphere. However, the queens were positioned alongside minimal rooms between them, which are an indication that the 300-foot requirement could not have been followed. The company did not provide safe work procedures such as initially placing the queens in a different position to eliminate the need to redirect to the CO₂ away from the next Queen. However, the company did not provide work procedures on where the employees should stand when opening the discharge valve. [Need an essay writing service? Find help here.]

Recommendations
The employer has issued a penalty and asked to abide by the worker’s compensation act sec 115 (2) (e) which states that the employer must provide employees with information, instructions, training and supervision to ensure the safety of the workers at work. Secondly, the organization issued a safety alert and the manufacturer made changes to the Queens by modifying the 4-inch blow line to vent at the rear of the queen, above the ground and out of the worker’s way.

References
Friend, M. A., & Kohn, J. P. (2007). Fundamentals of occupational safety and health. Lanham, Md: Government Institutes.

Hosseinian, S. S., & Torghabeh, Z. J. (2012). Major theories of construction accident causation models: A literature review. International Journal of Advances in Engineering & Technology, 4(2), 53-66.

Hoyos, C., & Zimolong, B. (2012). Occupational safety and accident prevention: Behavioral strategies and methods. Amsterdam: Elsevier.

Stranks, J. W. (2010). Health & safety at work: An essential guide for managers. London: Kogan Page.