Firefighters are called in many different emergency situations where there is the potential for exposure to hazardous materials. These hazardous materials can become airborne and present threats as dusts, fumes, smoke, gas, aerosols, mists, and vapors. The respiratory system is vulnerable to these airborne hazards especially when they present in a size small enough to be inhalable (<100 μm). Research has shown that the smoke firefighters are exposed to contain harmful inhalable particles during firefighting activities . These harmful particles create free radicals like carbon, hydrogen, and oxygen radicals that react with the airway to produce inflammation, fibrogenesis, and bronchopulmonary carcinogenesis  . Carbon-centered free radicals have been found to originate from wood fire and are known to specifically react within the bronchopulmonary tree . Additionally, ultrafine particles (0.042 - 0.24 μm) inhaled through wildfire smoke were found to be potent producers of malondialdehyde a byproduct of lipid peroxidation and H2O2 responsible for DNA damage .
The respiratory system injury due to occupational smoke inhalation can have both short and long-term adverse health implications. Studies have demonstrated that firefighters exhibit an inflammatory response after smoke inhalation. This inflammatory response results in increased sputum granulocytes, circulating cytokines, and circulating band cells . These inflammatory changes post smoke inhalation exposure have been correlated with changes in spirometry testing. Multiple studies demonstrate decreases in both forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) during spirometry testing . These decreases in spirometry testing and inflammatory changes (sputum granulocytes) persisted up to 3 months post exposure  . All of these findings suggest that smoke inhalation can lead to both acute and long-term adverse health effects in firefighters.
To protect against smoke inhalation firefighters use respirators. One must keep in mind that independent of the respiratory concerns, fire extinguishing activities take place in a very stressful environment. The environment in which firefighters work requires strenuous physical exertion, awkward positioning, extreme heat, low visibility, loud noise, and psychological stress . This creates significant physiological strain on all body systems but most directly on the cardiovascular and thermoregulatory systems. This strain can manifest itself by elevated core body temperature (hyperthermia), profuse sweating leading to a significant reduction in plasma volume (dehydration), decreased stroke volume, close to maximal heart rate (tachycardia), alterations in blood electrolytes, and disabling fatigue . Even with all of these stressors, using the actual respirator causes additional physiological strain on the body.
Studies on open circuit self-contained breathing apparatus (SCBA) type respirators demonstrate that there is added physiological stress from respirators due to increased airway resistance. When one uses a respirator there is increased physiologic dead space creating increased resistance especially during expiration. Inspiration is less affected due to assistance by the positive pressure systems within the respirator. The increased expiratory resistance reduces tidal volume resulting in hypoventilation thus reducing oxygen consumption. This occurs during a time when the body physiologically requires more oxygen as a result of the increased physiologic demand . Additionally, the actual mechanical weight of the respirator increases the physiological demand of the body. Much effort has been dedicated to characterization of the increased physiological demands during fire extinguishing activities. This information would better assist risk stratification during medical fitness assessment for firefighters. Unfortunately, due to the very nature of the fire extinguishing environment and the great physiological demands it has been a difficult task .
Still respirators do help protect workers from the adverse health effects due to the occupational hazard of smoke inhalation. Both the Occupational Health and Safety Administration (OSHA) and the National Fire Protection Association (NFPA) have produced standards and regulations regarding respiratory protection. Per OSHA 29 C.F.R. §1910.134 and NFPA Standards (1404, 1500, 1582, 1981, 1986, 1989) when atmospheric contamination against agents responsible for occupational diseases is not able to be prevented by accepted engineering control measures, appropriate respirators provided by the employer should be used. Additionally, when a workplace or an employer requires respirator use, the employer must maintain a written respiratory protection program. The written respiratory protection program outlines the following: procedures for selecting the proper respirator, medical evaluation for those employees required to use respirators, annual procedures for fit testing, procedures for proper respirator use, procedures for respirator maintenance, training on respirator use, training on respirator hazards, and procedures to evaluate the effectiveness of the respiratory program .
One of the most concerning aspects of a respiratory protection program is that non-compliance at any level may put firefighters at increased risk of injury and illness due to inhalation exposure. A survey of 281,776 private sector employers requiring respirator use showed that only 132,348 (47%) of employers evaluated medical fitness for respirator use. An additional 13,598 (5%) did not know about the requirement for medical fitness assessment prior to respirator use. Of those implementing medical fitness assessments, the modality of assessment was variable. The largest portion representing 62,893 employers (48%) used questionnaire with follow-up physical examination, 40,520 (31%) used physical examination only, 14,388 (11%) used questionnaire only, and 12,683 (10%) used other modalities. These variabilities existed even though the requirements from national organizations like the OSHA and the Mine Safety and Health Administrations which these employers follow are not variable and in fact are both explicit and clear .
The purpose of this research is to collect information regarding respiratory protection programs for Florida firefighters. Collected information will characterize practices, knowledge, and surveillance related to the respiratory protection programs. The primary goal is to identify risk factors for non-compliance with existing respiratory protection programs to fill the gap in research regarding factors that impact non-compliance with respiratory protection programs.
The study design is a cross-sectional survey of Florida fire departments in the Tampa area during the year 2015. The survey consisted of 21 questions that collected information regarding firefighter knowledge and participation in their respective respiratory protection programs during the previous 12 months. It was administered to 477 Florida firefighters both in person (44) and electronically (433). In addition to collection of information regarding respiratory practices, basic demographic information was obtained regarding respondent firefighters and their respective fire departments to evaluate potential bias in respondent rates. Survey questions were developed from the model set by OSHA and the NFPA which provides standards and regulations regarding firefighter protections. Additional input was received from a consultant with previous experience with a Florida fire department and faculty from the University of South Florida College of Public Health. Data was collected under USF IRB exemption IRB#: Pro00017811.
Collected data were used to produce summary statistics regarding firefighter and fire department demographic information related to gender, age, ethnicity, firefighter type, service years, department size, and department response area. Further data analysis was performed using Statistical Analysis Software (SAS) to compute multinomial logistic regression.
3. Results and Discussion
There were 477 respondents who completed the survey questionnaire. Firefighter age distribution shows that overall, the respondents were 91% male with a mean age of 39 years old (range 21 - 65 years). Seventy-six percent of firefighters were non-smokers, 21% former smokers, and 3% current smokers. Firefighter ethnicity distribution shows that respondents were 77% Caucasian, 13% Hispanic, 3% African American, and 4% other. Most respondents were career firefighters, 97%, working in a fire department with at least 21 firefighters, 98%. Forty-five percent of respondents had less than ten years of experience as a firefighter while 55% had greater than ten years of experience. The majority of fire departments included in the survey, 63%, worked in fire departments with a service area of less than 10,000 square miles.
3.1. Description of Firefighter Activities
Firefighter respiratory protection survey results (Table 1) display firefighter respiratory practices regarding several aspects of firefighter respiratory protection programs according to the NFPA guidelines. Of respondents, 73% always use respirators when responding to a fire and 90% maintain respirator use during firefighting activities. Half of respondent firefighters, 50%, performed fireground monitoring prior to doffing respirators. The majority of respondent firefighters, 89%, performed first responder/emergency medical technician/paramedic activities as compared to 8% hazardous materials operations, 8% search and rescue operations, and 4% water rescue and diving operations. Half of respondent firefighters, 50%, only use respirators during fire extinguishing activities and 97% use the SCBA type respirator.
Table 1. Firefighter respiratory protection survey results.
EMT = Emergency Medical Technician; HAZMAT = Hazardous Materials; SCBA = Self-Contained Breathing Apparatus; NFPA = National Fire Protection Association; OSHA = Occupational Safety and Health Administration.
3.2. Multinomial Logistic Regression
Table 2 displays which demographic factors were associated with recorded firefighter knowledge and practices regarding the respiratory protection program. The associations measured in the multinomial logistic regression are displayed as odds ratios (OR) and 95% confidence intervals (CI). In regards to respirator use activities, the multinomial logistic regression shows that a larger fire department with at least 20 members had a 0.186 OR (0.035 - 0.974 CI) of using a respirator as compared to a smaller fire department with 1 - 10 members and less than 10 years of service experience had a 1.939 OR (1.240 - 3.034 CI) of not
Table 2. Statistically significant results from the multinomial logistic regression.
EMT = Emergency Medical Technician; HAZMAT = Hazardous Materials; SCBA = Self-Contained Breathing Apparatus; OSHA = Occupational Safety and Health Administration.
using a respirator in non-fire situations as compared to greater than 10 years of service experience. Additionally, respondents from fire departments with a 100,000 - 250,000 versus less than 10,000 square miles response area had a 4.964 OR (1.243 - 19.827 CI) of using an SCBA type respirator. Fireground quality sampling and monitoring prior to doffing respirator was associated with both being a former smoker, 1.719 OR (1.050 - 2.813 CI) versus never smokers, and less than 10 years of service experience, 1.690 OR (1.012 - 2.558 CI) versus greater than 10 years of service experience.
3.3. Written Respiratory Protection Program
Regarding the written respiratory program, 83% of respondents confirmed their department had a written respiratory protection program while, 14% did not know, and 3% responded that their department did not have a written respiratory protection program. This corresponds to 83% of respondents who confirm that they are familiar with their department’s respiratory program. Essentially all fire departments, 99%, had policies in place regarding facial hair, sideburns, and/or glasses that would prevent proper respirator fit according to respondents. Additionally, most fire departments followed specific OSHA and NFPA guidelines, 90% OSHA 1910.134 “Two-in & Two-out” rule, 88% NFPA 1404, and 84% NFPA 1500. Logistic regression shows that a greater than 250,000 square miles response area had a 0.444 OR (0.219 - 0.901 CI) of having written respiratory program as compared to a less than 10,000 square miles response area. In regard to OSHA 1910.134 “Two-in & Two-out” rule, responding Other for ethnicity had a 0.169 OR (0.058 - 0.497 CI) when compared to responding Caucasian for ethnicity.
3.4. Barriers to Written Respiratory Protection Program
None of the firefighters surveyed listed lack of financial resources as a reason for not having a written respiratory protection program. The most cited reasons for not having a written respiratory protection program include lack of knowledge (1%), it is not required (1%), and other reasons (5%). Even with the opportunity for free text responses during survey completion, there were no free text responses associated with the Other response for not having a written respiratory protection program.
3.5. Respiratory Training and Fit Testing
Nearly all of respondents, 99%, confirmed that they had received both training for respirator use and respirator fit testing. Specific to fit testing 78% received annually fit testing, 14% received fit testing every six months, and 8% as needed. Logistic regression shows that annual fit testing was associated with both ethnicity and fire department response area. Responding Other for ethnicity had a 0.372 OR (0.144 - 0.960 CI) when compared with responding Caucasian for ethnicity in regard to having annual fit testing. A fire department with a 25,000 - 50,000 square miles response area had a 0.336 OR (0.119 - 0.950 CI) for having annual fit testing as compared to a less than 10,000 square miles response area.
Quantitative testing was most commonly performed according to 72% respondents. This is contrasted with 10% of respondents undergoing qualitative testing and 20% of respondents not knowing which type of fit testing they received. Having less than 10 service years experience had a 2.160 OR (1.296 - 3.600 CI) of having quantitative testing as compared to greater than 10 service years experience. Conversely less than 10 service years experience had a 0.540 OR (0.321 - 0.907 CI) of having qualitative testing as compared to greater than 10 service years experience.
3.6. Respirator Medical Fitness Assessment
The majority of respondents, 77%, reported having a medical assessment prior to being approved to use a respirator. Those with medical assessments most often reported being evaluated by an occupational health nurse (36%), followed by occupational medicine physician (22%), unknown (18%), primary care physician (5%), and other (5%). Logistic regression demonstrates that a response area of 50,000 - 100,000 square miles had a 2.847 OR (1.022 - 7.933 CI) of having a medical assessment from an occupational medicine physician as compared to having a less than 10,000 square miles response area. 18% percent of respondents reported not having a medical assessment which corresponds with 16% of respondents indicating that no one performed the medical assessment. Only 45% of respondents reported having at least annual medical fitness testing (annual 43%, every six months 2%).
Logistic regression demonstrates multiple associations with having annual medical fitness testing: former smoker 0.600 OR (0.385 - 0.933 CI) as compared to never smoker, African-American ethnicity 3.222 OR (1.025 - 10.128 CI) as compared to Caucasian ethnicity, and greater than 250,000 square miles response area 0.528 OR (0.312 - 0.894 CI) as compared to less than 10,000 square miles response area. The reported experience regarding how the medical fitness testing was performed was varied with 28% reporting use of all modalities (questionnaire, physical examination, and spirometry), 39% reporting that the modality was unknown, and 27% reporting a specific combination of the modalities. Logistic regression shows multiple associations with modality of medical fitness testing. Having questionnaire as the only modality had a 0.483 OR (0.249 - 0.937 CI) of being associated with a greater than 250,000 as compared to a less than 10,000 square miles response area while using all modalities had a 0.114 OR (0.014 - 0.943 CI) of being associated with a fire department size of greater than 20 as compared to 1 - 10. Having a medical questionnaire with follow up physical examination as needed for medical fitness testing demonstrated a 0.122 OR (0.020 - 0.760 CI) when comparing volunteer with career type firefighter and a 0.090 OR (0.011 - 0.722 CI) when comparing a fire department size of greater than 20 with 1 - 10. Medical fitness evaluation with physical examination only demonstrated a 9.232 OR (1.511 - 56.394 CI) when comparing a fire department size of greater than 20 with 1 - 10 and a 0.348 OR (0.145 - 0.833 CI) when comparing a 50,000 - 100,000 square miles response area with a less than 10,000 square miles response area. Medical fitness testing with spirometry demonstrated a 0.081 OR (0.016 - 0.405 CI) when comparing combination volunteer/career with career type firefighter and a 0.363 OR (0.185 - 0.712 CI) when comparing greater than 250,000 square miles response area with less than 10,000 square miles response area.
The demographic data on both firefighters and fire departments suggests that there was not a large amount of diversity among the firefighters who completed the survey. The majority of those surveyed were Caucasian male career firefighters who never smoked from fire departments with 21 or more members responsible for a service area that is less than 10,000 square miles. Other than Caucasian ethnicity (77%), status of never smoker (76%), and a less than 10,000 square miles service area (63%), these characteristics describe greater than 90% of the survey respondents. This lack of diversity limits our ability to understand the differences within this group and suggests that the respondent firefighters belong to a small group of fire departments.
Even so multinomial logistic regression found differences among the firefighters and fire departments. Smaller fire department size, 1 - 10 members, and less than 10 years of service experience were associated with not using a respirator during non-fire activities. These associations provide little insight into compliance with the respiratory protection program. This association likely shows that smaller fire departments and firefighters with less experience are less likely to perform advanced techniques that require respirators in non-fire situations. The finding that the relatively large fire department service area of 100,000 - 250,000 as compared to less than 10,000 square miles was associated with SCBA type respirator use is less meaningful given neither a statistically significant association nor a directional trend was found when other response area sizes including the largest response area group, greater than 250,000 square miles, were assessed. The finding that being a former smoker and having less than 10 years of service experience was associated with fireground monitoring prior to respirator doffing suggests perceived respirator risk plays an important role in this activity. Former smokers are likely to have more baseline lung damage than never smokers and thus be more sensitive to poor air quality and respiratory occupational exposure  . Additionally, less experienced firefighters are more likely to perceive higher risk during fire extinguishing activities and be more cautious about the potential for poor air quality and respiratory occupational exposure.
Specific to the written respiratory protection program, logistic regression analysis found fire departments with a greater than 250,000 square miles response area were negatively associated with having a written respiratory protection program as compared to fire departments with a less than 10,000 square miles response area. Even though the survey did not collect specific information to determine whether a fire department had an urban or rural location, service area can be used as a surrogate as those fire departments covering a greater response area are more likely to be rural. This would suggest that urban fire departments were more likely to have a written respiratory protection program as compared to rural fire departments. These findings are consistent with previous data which suggested that urban fire departments with more funding, more resources, and less volunteer fire departments were associated with compliance with the requirement for a written respiratory protection program . There were no statistically significant findings regarding barriers to compliance with the requirement for a written respiratory protection program. This is most likely due to insufficient power to find differences regarding barriers as 93% of respondents recorded not applicable in the survey question on barriers to compliance.
There were firefighter demographic level differences among specific aspects of the respiratory protection program. Caucasian ethnicity was associated with compliance with the OSHA 1910.134 “Two-in & Two-out” rule and having an annual respirator fit test as compared to other ethnicities. It is difficult to draw conclusions from this as 4% of respondents classified themselves as Other and within the Other ethnicity there were eight unique responses for ethnicity. African American ethnicity was associated with annual medical fitness testing recommended by respiratory protection program guidelines as compared to Caucasian ethnicity. Similarly it is difficult to draw meaningful inferences regarding respiratory protection program compliance from this association given that this response is compared against four unique responses, “at least every six months”, “never”, “other”, and “unknown” only one of which (never) can be equated to non-compliance. Logistic regression also found that annual respirator medical fitness testing was negatively associated with former as compared to never smoker status. Unfortunately, one is not able to interpret this to suggest that former smoker status is associated with noncompliance as only one of the other four unique responses is consistent with non-compliance, “never”. Additional firefighter level demographics showing statistically significant differences were found in quantitative fit testing which was associated with less experience. As both quantitative and qualitative fit testing is recognized as valid by OSHA, this difference represents little importance in regard to compliance with the respiratory protection program .
There were fire department demographic level differences among both the frequency of fit testing and the frequency of medical fitness testing. Urban fire departments, as suggested by a less than 10,000 square miles response area, were associated with both annual fit and medical fitness testing. This finding is consistent with previous studies suggesting urban as compared to rural fire departments have more resources to be in compliance with the respiratory protection guidelines. Annual fit testing only showed statistical significance comparing a less than 10,000 square miles response area with a response area of 25,000 - 50,000 square miles and not greater than 250,000 square miles. This suggests that more urban fire departments were more likely to have the mandated annual testing. Unfortunately, this association was not found when other response areas were compared nor was there a trend found regarding response area size. Of note similar to the firefighter level differences found regarding annual medical fitness testing, the unique responses other than annual medical fitness or fit testing were not necessarily associated with non-compliance thus reducing the strength of association these findings have with respiratory protection program compliance.
Being evaluated by an occupational medicine physician was associated with a 50,000 - 100,000 square miles response area as compared to that of less than 10,000 square miles. Similarly this is difficult to interpret as a response area of greater than 250,000 square miles is most clearly associated with rural fire departments. At the same time medical fitness testing by an individual other than an occupational medicine physician suggests but is not necessarily consistent with NFPA guideline non-compliance. The guidelines state that the fire department physician will make determination of medical certification with a medical evaluation which includes a medical examination. Medical examination is defined as an “examination performed or directed by the fire department physician”. Being a fire department physician is not specific to occupational medicine physicians and a non-physicians clinician working under the direction of the fire department physicians would satisfy this definition of a medical examination.
There was a great amount of variability among the different modalities for annual fit testing. Small urban fire departments were associated with using all modalities as compared to large rural fire departments. When different specific modality combinations were evaluated, small urban fire departments were also associated with physical examination and spirometry testing. These findings are consistent with prior research suggesting that urban departments have more resources and thus can perform the full complement of modalities and have access to the more advanced equipment required for spirometry and medical assessment beyond medical questionnaire . Career firefighters were associated with the modality of spirometry testing and the modality of questionnaire with follow up physical examination for medical fitness assessment. This is also consistent with prior research suggesting that career type fire departments have more resources as compared to volunteer type fire departments .
Overall, Florida fire departments are doing a good job of implementing their respiratory protection programs. Even so there are firefighters who are potentially inadequately protected against the occupational hazard of smoke inhalation. Additional attention needs to be given to Florida fire departments to ensure that all firefighters receive adequate respiratory protection in accordance with both OSHA and NFPA guidelines. The study finding that urban fire departments do a better job of being in compliance with the guidelines as compared to rural departments is consistent with prior research regarding fire department compliance. Additional research should focus on why these differences exist in the rural fire departments. The differences are likely not related to funding as no respondents cited this as a reason for not having a written respiratory protection program. More effective training and overall program robustness likely play a key role in the differences found as many respondents stated or demonstrated a lack of knowledge regarding respiratory protection program requirements. Future research efforts should focus on fire department respiratory protection education and training.
This research was funded by the NIOSH Sunshine Education Research Center, College of Public Health, University of South Florida, Tampa, FL.
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