HD599 Unit 4 Evidence Synthesis Example

Four Questions, One Gap: A Unit 4 Evidence Synthesis for a Volunteer Fire District's Post-Fire Exposure Capstone

[Student Name]

Purdue University Global

HD599: Master's Capstone in Health Education and Promotion

Unit 4 Evidence Synthesis

[Instructor Name]

[Date]

Kessling Valley Fire Protection District and its decisions are composite; every study cited is real and described from its published findings.

How This Synthesis Is Organized

The district will make four separate decisions during the project: how strongly to state the risk to members, which on-scene steps to require, how to get members to perform them, and what to do about gear that travels home in private vehicles. Each decision gets its own question and its own section. A synthesis arranged source by source would leave the chief and the training officer to reassemble the evidence themselves.

Strength is rated on a three-level scale defined here and used throughout. Strong means consistent findings from several field or exposure studies. Limited means few studies, mixed results or designs that cannot separate cause from correlation. Little or none means the question has barely been studied. Each section ends with a line on how far the findings transfer to Kessling Valley's volunteers, because nearly every study comes from a career department.

Question 1: What Reaches a Firefighter After the Fire

The stakes are settled at the level of classification. In 2022 an expert panel convened in Lyon by the cancer research arm of the World Health Organization concluded that occupational exposure as a firefighter is carcinogenic to humans, the highest category, on the basis of sufficient evidence for mesothelioma and bladder cancer and strong mechanistic evidence (Demers et al., 2022).

Exposure studies show how that risk reaches the body. Personal air sampling during overhaul, the phase after visible fire is out, has found particulates and polycyclic aromatic hydrocarbons at levels that justify continued respiratory protection, at a time when many firefighters have removed their masks (Baxter et al., 2014). Controlled residential fires with instrumented crews found contamination on turnout gear and on skin, with the neck among the most contaminated sites measured (Fent et al., 2017). The neck sits under the hood, which is a knit layer that absorbs smoke and is pulled on and off by hand. Laundering studies have since shown that hoods retain contaminants and that a standard wash removes much, though not all, of what they carry (Mayer et al., 2019).

Biomonitoring links these surface findings to absorbed dose. Urine samples from on-shift firefighters in Ottawa showed elevated levels of polycyclic aromatic hydrocarbon metabolites and mutagenic activity after fire suppression compared with before (Keir et al., 2017). Wipe samples from two fire stations in the United Kingdom found carcinogenic hydrocarbons on firefighters' jaws, necks and hands, on helmets and clothing, and on surfaces in the stations and engines themselves, and the authors judged skin absorption the main route of exposure (Stec et al., 2018). Contamination, in other words, does not stay on the fireground.

Strength: strong for contamination of gear, hood and skin; strong for absorbed exposure in career crews.

For Kessling Valley: the hood and neck deserve their own steps in the guideline, and the risk can be stated plainly to members without exaggeration.

Question 2: What On-Scene Decontamination Removes

The best field evidence comes from the same controlled fires. Gross decontamination of turnout gear on scene with water, dish soap and a brush reduced contamination on the outer shell for most compounds measured, and commercial skin wipes reduced contamination on the neck (Fent et al., 2017). The reductions were substantial but incomplete, and they varied by compound.

A field evaluation in Arizona tested a package of fireground changes in career departments: breathing apparatus worn by engineers at the pump, a wash down of the entry team, contaminated equipment kept out of the cab, and showers and gear washing on return to the station. Urinary hydrocarbon metabolites measured after structure fires fell by roughly 40 percent in engineers and 36 percent in firefighters after the changes, but captains showed no significant reduction (Burgess et al., 2020).

The evidence supports on-scene decontamination for what it removes from gear and skin, and one package of fireground changes lowered absorbed dose for most crew positions, but no study promises that brushing and wiping remove everything, so the guideline should present the steps as reducing exposure, not eliminating it.

Strength: strong for reduction on outer gear and on the neck; limited for reduction in absorbed dose, which rests mainly on one before-and-after evaluation.

For Kessling Valley: water, soap, brush and skin wipes on scene, plus a clean hood, are supported. The cold-weather problem the district faces in winter is not addressed by these studies, which were run in mild conditions.

Question 3: What Changes Firefighters' Habits

This literature is thinner and mostly descriptive. A survey of 485 firefighters from four departments in Florida found positive attitudes, beliefs and perceived norms about decontamination, yet showering after a fire was the only step performed regularly; field decontamination, cleansing wipes and routine gear cleaning all happened less often. Respondents named time and concern about wet gear as the main barriers (Harrison et al., 2018). The gap between favorable attitudes and actual practice is the finding most relevant to a health educator.

Intervention studies of behavior itself are scarce. The Arizona evaluation changed procedure at the department level and measured absorbed exposure, not whether individual firefighters adopted each step or why (Burgess et al., 2020). No study found in the search tested drills, officer prompts or peer leaders as ways to raise decontamination rates.

Strength: limited. Barrier surveys agree with one another, but they are cross-sectional and from career departments, and no trial of a behavioral approach was found.

For Kessling Valley: the barriers to expect are time and wet gear, and a cold night will make wet gear worse; the project's own survey can confirm or correct the list and add missing spare hoods if members name them. The district's officer radio call and drills are reasonable designs, but they rest on behavior theory, not on firefighter trials.

Question 4: Volunteers and Gear in Private Vehicles

This question returned almost nothing. Searches combining volunteer or rural fire service terms with decontamination, contamination or cancer prevention found surveys of volunteer recruitment and stress, but no exposure or decontamination study set among volunteers who respond from home and return in personal vehicles. The closest evidence is indirect: hydrocarbons found on station surfaces and inside engines, which shows contamination travels wherever gear goes (Stec et al., 2018), the Arizona finding that keeping contaminated equipment out of the cab was part of a package that lowered absorbed dose (Burgess et al., 2020), and laundering results showing that contaminants stay in hoods until they are washed (Mayer et al., 2019). None of these studies measured a private car.

Strength: little or none.

This gap is a finding, not an apology. It means the practices the district is asking volunteers to adopt, bagging gear and carrying it outside the passenger compartment, are reasoned from career-department evidence rather than tested among volunteers. It is also the reason the project's own exposure form, with its new field for how gear traveled home, matters beyond the district.

What the District Can Take From the Evidence

Three implications follow for the practice deliverable.

First, the guideline should give the hood and neck their own steps: a clean hood from the engine and a skin wipe for neck, jaw and hands before the member leaves the scene.

Second, the guideline should describe on-scene decontamination as reducing exposure, in line with what the field studies showed, and should include a cold-weather variant the studies did not test, labeled as a local adaptation.

Third, the vehicle rule should be presented as a precaution reasoned from indirect evidence, and the project should report what the new form field shows so the district's own experience adds to a near-empty literature.

Limits of This Synthesis

The search covered peer-reviewed journals and agency reports available through the university library and did not include unpublished department data. Most included studies come from career departments in large cities, so all transfer judgments are the writer's. The writer is a member of the district, which may bias the reading toward evidence that supports the planned intervention; each strength rating was checked against the defined scale to limit that bias.

References

Baxter, C. S., Hoffman, J. D., Knipp, M. J., Reponen, T., & Haynes, E. N. (2014). Exposure of firefighters to particulates and polycyclic aromatic hydrocarbons. Journal of Occupational and Environmental Hygiene, 11(7), D85-D91. https://doi.org/10.1080/15459624.2014.890286

Burgess, J. L., Hoppe-Jones, C., Griffin, S. C., Zhou, J. J., Gulotta, J. J., Wallentine, D. D., Moore, P. K., Valliere, E. A., Weller, S. R., Beitel, S. C., Flahr, L. M., Littau, S. R., Dearmon-Moore, D., Zhai, J., Jung, A. M., Garavito, F., & Snyder, S. A. (2020). Evaluation of interventions to reduce firefighter exposures. Journal of Occupational and Environmental Medicine, 62(4), 279-288. https://doi.org/10.1097/JOM.0000000000001815

Demers, P. A., DeMarini, D. M., Fent, K. W., Glass, D. C., Hansen, J., Adetona, O., Andersen, M. H., Freeman, L. E. B., Caban-Martinez, A. J., Daniels, R. D., Driscoll, T. R., Goodrich, J. M., Graber, J. M., Kirkham, T. L., Kjaerheim, K., Kriebel, D., Long, A. S., Main, L. C., Oliveira, M., . . . Schubauer-Berigan, M. K. (2022). Carcinogenicity of occupational exposure as a firefighter. The Lancet Oncology, 23(8), 985-986. https://doi.org/10.1016/S1470-2045(22)00390-4

Fent, K. W., Alexander, B., Roberts, J., Robertson, S., Toennis, C., Sammons, D., Bertke, S., Kerber, S., Smith, D., & Horn, G. (2017). Contamination of firefighter personal protective equipment and skin and the effectiveness of decontamination procedures. Journal of Occupational and Environmental Hygiene, 14(10), 801-814. https://doi.org/10.1080/15459624.2017.1334904

Harrison, T. R., Muhamad, J. W., Yang, F., Morgan, S. E., Talavera, E., Caban-Martinez, A., & Kobetz, E. (2018). Firefighter attitudes, norms, beliefs, barriers, and behaviors toward post-fire decontamination processes in an era of increased cancer risk. Journal of Occupational and Environmental Hygiene, 15(4), 279-284. https://doi.org/10.1080/15459624.2017.1416389

Keir, J. L. A., Akhtar, U. S., Matschke, D. M. J., Kirkham, T. L., Chan, H. M., Ayotte, P., White, P. A., & Blais, J. M. (2017). Elevated exposures to polycyclic aromatic hydrocarbons and other organic mutagens in Ottawa firefighters participating in emergency, on-shift fire suppression. Environmental Science & Technology, 51(21), 12745-12755. https://doi.org/10.1021/acs.est.7b02850

Mayer, A. C., Fent, K. W., Bertke, S., Horn, G. P., Smith, D. L., Kerber, S., & La Guardia, M. J. (2019). Firefighter hood contamination: Efficiency of laundering to remove PAHs and FRs. Journal of Occupational and Environmental Hygiene, 16(2), 129-140. https://doi.org/10.1080/15459624.2018.1540877

Stec, A. A., Dickens, K. E., Salden, M., Hewitt, F. E., Watts, D. P., Houldsworth, P. E., & Martin, F. L. (2018). Occupational exposure to polycyclic aromatic hydrocarbons and elevated cancer incidence in firefighters. Scientific Reports, 8, 2476. https://doi.org/10.1038/s41598-018-20616-6