3.1. Methodology
A retrospective analysis of Western Australian fire service safety and incident reports between January 1st, 2001 and January 1st, 2015 was conducted. All of these reports related to incidents responded to by frontline operational fire and emergency services. All information that could identify personnel was redacted prior to collection by the lead investigator. A total of 1997 individual reports were initially analysed. Ethics approval was obtained through Edith Cowan University postgraduate research services, whilst Department of Fire and Emergency Services (DFES) permission for the study was provided by then-Commissioner Wayne Gregson APM. To ensure data reflected injuries sustained during operational events, the following inclusion criteria were applied:
For the purposes of this study, “injury” was defined as any adverse outcome that was physical or psychological in nature. The term “operational incident” was defined as an incident assigned an internal incident identification number and responded to by personnel. Following application of the inclusion criteria, 666 reports were identified as suitable for analysis. Data were initially categorised according to:
Activity (being the primary task undertaken at the time of the reported incident);
Initiating event (being the risk source);
Nature of the injury reported;
Actual severity of the consequence reported; and
Potential severity of the consequence reported.
The severity of the consequence was extrapolated from the report description and classified according to Department of Fire and Emergency Services policy [
3]:
Insignificant—no treatment required; no lost time;
Minor—first aid treatment only; no lost time;
Moderate—medical treatment; lost time—less than 10 days lost;
Major—hospitalisation/significant injury; lost time—more than 10 days lost; and
Catastrophic—severe permanent injury/disability/fatality(ies).
The potential severity of the consequence was determined by selecting the highest consequence from both the reports collected and review of comparative incident reports from the Federal Emergency Management Agency [
17]. The same categories of consequence were applied as above.
Activity at the time of injury and nature of the injury sustained was extrapolated from the incident reports to facilitate probability modelling; determination of severity of the actual and potential consequence; and calculation of incident likelihood. Likelihood was determined using the formula:
Likelihood was defined in accordance with DFES policy [
3]:
Rare—may only occur in exceptional circumstances (once in 10 years);
Unlikely—could occur at some time (once in 5 years);
Moderate—should occur sometime (once in 2 years);
Likely—will probably occur in most circumstances (at least once per year); and
Almost certain—expected to occur in most circumstances (more than once per year).
For illustrative purposes utilising notional figures, if there were 18 reported ankle injuries over the 15-year period, the frequency of ankle injury would be 18/15 or 1.20 ankle injuries per year, equating to a likelihood rating of almost certain. If there were only two reported ankle injuries over the same time period, then the frequency would be 2/15 or 0.13 ankle injuries per year, equating to a likelihood rating of rare.
Data relating to the type of activity undertaken at the time of injury and the nature of the injury sustained were analysed using Bayesian statistics to determine the overall and conditional probability of specific injuries being sustained during the various tasks undertaken during an emergency incident. In this manner, the overall probability of specific outcomes was determined using the formula:
where:
P(A∩B) is the probability that both A and B occur;
P(A) is the probability that A will occur; and
P(B) is the probability that B will occur.
Conditional probability was calculated by:
where:
P(A|B) is the probability that A will occur given the fact that B has already occurred;
P(A∩B) is the probability that both A and B occur; and
P(B) is the probability that B will occur.
For illustrative purposes utilising notional figures, subsequently referred to as Scenario A, if there were 11 reported ankle injuries out of 666 total reported injuries across all incidents, then the probability of an ankle injury (A) is 0.017. If there were 36 injuries reported to have occurred during a rescue operation, then the probability of an injury being sustained during a rescue operation (B) is 0.054. Therefore, the probability of an ankle injury occurring during rescue operation is sustained is:
By comparison and using the same notional figures, the conditional probability (P(A|B)) of an ankle injury being sustained, given an injury is sustained during a rescue operation, is 0.306.
The analysis was repeated for each activity, risk source, and injury to determine the conditional probability of:
A specific injury being sustained (A) given an injury is sustained during a certain task at an incident (B);
A certain consequence severity occurring based on historical data (A) given an injury is sustained during a certain task at an incident (B); and
A certain potential consequence was possible (A) given an injury sustained during a certain task at an incident (B).
3.2. Results and Discussion
Using Excel spreadsheets, analysis enabled the calculation of conditional probability given a reportable incident occurs, and likelihood on the basis of activity, risk source, and nature of injury reported. Whilst full results are provided as an
Appendix to this report, the five most likely results are detailed in
Table 1,
Table 2 and
Table 3. Each table is ordered from highest to lowest frequency.
By frequency, firefighting was almost three times more likely to result in a reportable event compared to any other activity with an occurrence of 21.8 times per year. Road crash rescue (RCR) response resulted in 7.3 reportable events per year, whilst bushfire fighting resulted in 6.6 reportable incidents per year. This result suggests additional attention should be provided in training personnel and developing suitable risk mitigation procedures for the activities most likely to give rise to a reportable incident, for example, firefighting, RCR, and bush firefighting.
In terms of risk source, physical strain is almost 1.8 times more likely to result in a reportable event compared to other risk sources. This is consistent with the physically demanding nature of firefighting [
24] and is comparable to overexertion/strain injury rates in United States firefighters [
17].
Exposure to various hazards, including asbestos, chemicals, and biohazards, collectively accounts for more reports than any other risk source (total of 225 incidents with a conditional probability of 0.338).
Just as firefighting is extremely physically demanding, it is also psychologically demanding with exposure to psychological trauma or stress identified as the second most common risk source resulting in reportable events. Carll [
25] and Trappler [
26] concur that care must be taken in addressing risks arising from exposures of a psychological nature in firefighting which are unique to the emergency service profession. Just as education, awareness, and resilience training is important prior to exposure to events of a psychological nature, specific psychological management programs and counselling are required post-exposure.
Analysis by injury yields results that, in limited circumstances, appear to conflict with other available data sets. Inhalation ‘injuries’ are the most probable of all classified injuries to occur. However, this may be explained by the fact that all reported incidences of “inhalation” of smoke or other chemicals were captured in this category, regardless of whether acute injury occurred. Psychological ‘injuries’ were the second most common reported injury, and this is consistent with the analysis of risk source data. Surprisingly, thermal injuries, being those resulting from heat transfer, were the least probable (0.002 conditional probability). This conflicts with data reported by FEMA [
16,
17] which identify a significantly higher thermal injury occurrence rate. The number of thermal injuries reported in this study may be lower than the true number of injuries because many incidents may remain unreported. The probability of “nil” injuries occurring represents “near misses” where no injury was actually sustained and is the third highest amongst reported injuries sustained. Again, this figure may be lower than the true number of near misses that occur during incidents because of a lack of report completion when near misses occur.
Table 4 reports the conditional probability of a specific injury occurring given an injury occurs during the specified activity. The five most likely injuries for each activity are identified in the table. Across all activities, the “nil” injury or “near miss” is prevalent. This is consistent with previous findings and suggests a large number of incidents occur with the potential to cause injury but do not actually cause injury in the specific case reported. Psychological injuries are also well represented throughout the reports, particularly where the potential or realisation of human trauma is present (for instance road crash rescue and suicide response). In the case of reported injuries during suicide response, it is suggested it is likely the “not reported” values should also be psychological injuries even though they have not been documented as such in the relevant reports.
Analysis reveals thermal injuries account for a relatively insignificant conditional probability of only 0.003 during firefighting activities only. No thermal burns are reported during bushfire or other responses. This is in stark contradiction to the probability of thermal injuries reported in United States statistics [
16,
17]. However, it is hypothesised that this may be due to underreporting of thermal injuries, or due to thermal injuries being referred to as injuries to specific body parts without reference to the burn trauma, or due to differences in firefighting tactics between Australia and the United States, which may result in different mechanisms and frequencies of injury.
For example, inhalation injuries appear overrepresented in the data, which is considered surprising given the significant respiratory protection available to responding crews [
27,
28]. Analysis of descriptions with the reports suggests a significant proportion of inhalation exposures may be due to partial face-fitting respiratory protection masks that do not completely prevent ingress of smoke and other products of combustion. This has been rectified since the study commenced, through the implementation of full-face respirators available for firefighting personnel. The conditional probability of heat illness occurrence also warrants attention with prevalence amongst all operations and responses that require the responder to wear structural firefighting personal protective equipment (PPE). Wearing PPE requires significant physical effort.
Review of the conditional probabilities detailed above should assist ICs having enhanced evidence-based awareness of potential consequences and likelihoods prior to their occurrence during an emergency incident. Analysis of the conditional probability of injury given an injury occurs during each of the specific operations will also facilitate the review and improvement of strategic and tactical planning; personnel relief requirements; the potential effectiveness of PPE; and even guide the potential development of targeted prophylactic physical training programs.
Table 5 provides useful data to facilitate the development of evidence-based risk mitigation strategies prior to and on the incident ground. The five most likely injuries are identified in the table. Physical strain recurrently accounts for high, if not the highest, level of risk source, giving rise to a reportable incident across almost all activities. This finding is consistent with the previous results of both this study and that of FEMA [
16] and reaffirms the notion that firefighting is extremely physical in nature [
24]. It is suggested that a lack of physical wellness may be the primary contributor to reportable incidents as a result of physical strain. For example, Moore-Merrell et al. [
29] reported that physical strain was the second highest contributing factor to firefighter injury in the United States (the first being a lack of situational awareness).
Psychological exposure was also well represented in the data, particularly amongst incident response involving human life and trauma including road crash rescue and suicide response. This again supports previous findings of the study.
Exposure to various contaminants was also prevalent throughout the majority of fields. This may be significant as potential effects may be mitigated through appropriate strategic and tactical response; appropriate PPE; and suitable decontamination procedures [
23,
27,
28].
Breathing apparatus operations are amongst the most hazardous of all firefighting activities. These operations involve the use of self-contained breathing apparatus in atmospheres not conducive to life due to the presence of smoke, heat, oxygen deficiency, and/or excessive temperature [
27]. During breathing apparatus operations, teams of two firefighters will work in close proximity to, or inside, burning structures. Typically, they rely on a single line of firefighting hose for fire protection. The margin for error is therefore understandably narrow and the severity of potential consequences comparatively high (as reported in
Table 6). Breathing apparatus operations are extremely physical in nature, and this is represented by a conditional probability of 0.55 that the responsible risk source for the reportable event will be physical strain. Analysis also revealed a conditional probability of impacts being the responsible risk source for the reportable incident of 0.15. It is suggested impacts (as compared with explosion/blasts) are more likely to occur within a burning structure. Subsequently, this figure may be reduced through the defining of organisational risk acceptance thresholds. In turn, this would facilitate a reduction in the potential for ICs committing crews to internal firefighting in the absence of life involvement because of a perceived internal or external obligation to do so.
Table 6 provides the comparisons between actual reported consequence severity and potential consequence severity for each activity. The five most likely injuries are identified in the table. Analysis reveals the conditional probability of moderate to catastrophic potential consequence severity is higher than actual reported consequence severity across all activity groups. In part, this may be explained by the lack of subsequent reports or follow-up detail for consequences that may have a long period of latency (for instance, psychological exposures, or exposures to contaminants), or for injuries that are initially reported but worsen over time. Results of this analysis also support previous findings of the prevalence of “nil” reported injuries in that there is a high conditional probability of “near misses” within the incidents reported.
Further analysis reveals that, based on actual consequence severity, there was a conditional probability of zero (0.000) for a consequence of catastrophic severity occurring across the entire activity range. This result is not consistent with numerous international studies [
16,
17,
29] and, whilst acknowledging the differences in incidents responded to in different jurisdictions, this result potentially suggests Western Australian firefighting strategies are safer than those utilised by international counterparts. By comparison, a mean potential consequence of catastrophic severity revealed a conditional probability across all activities of 0.408 (standard deviation of 0.328). These results represent a significant potential for increased severe injury, permanent disability, and even death amongst the study group and should be considered in the establishment of the internal context for risk management during dynamic emergency operations.