Fire Fighters: Respiratory Protection and Lung Injury

1. Fire Fighters: Respiratory Protection and Lung Injury Jefferey L. Burgess, MD, MPH Associate Professor, Environmental and Occupational Health University of Arizona College of Public Health

2. Acrolein Benzene Carbon Monoxide Hydrogen chloride Hydrogen cyanide Nitrogen dioxide Particulates Polycyclic aromatic hydrocarbons (PAHs) Sulfur dioxide and thousands more Smoke exposure

3. Firefighter heatlh • Older studies demonstrated accelerated rates of decline in pulmonary function • Recent longitudinal studies demonstrate stable spirometry results • Continuing exposure to products of combustion • Continued concern over elevated cancer rates

4. Phases of firefighting • Entinguishment (knockdown) • Entry/ventilation • Rescue • Support/standby • Overhaul

5. Questions • Self-contained breathing apparatus (SCBA): how much protection do they provide? • Is spirometry alone adequate for medical surveillance of firefighters? • What type of respiratory protection is needed for firefighters during overhaul?

6. SCBA performance • NIOSH recommended PF of 10,000 • When inhalation rate exceeds respirator supply, facepiece pressure will become transiently negative. • If there is a leak, contamination with products of combustion may occur. • The degree of contamination will depend on facepiece fit and extent of negative pressure excursions.

7. 102 of 440 firefighters were fit-tested during fourteen shifts at eight stations. Virtually all the firefighters present in each station volunteered for fit-testing. Fit-testing used a single Scott AV-2000 large facepiece and a Dynatech Nevada FitTester. Fit-testing

8. CNP Fit-tests for Tucson* Mean Leak (cc/min) All (%) Large (%) <2.5 66 68 2.6-10 15 16 10.1-50 9 8 50.1-100 3 8 101-500 5 8 >500 4 2 *Fit-testing using a large facepiece. All refers to all firefighters tested, large refers to firefighters fit with a large facepiece

9. Treadmill testing • Firefighters previously fit for personal facepieces using irritant smoke. • Firefighters fitted with a large facepiece were eligible for the treadmill study. • 90% volunteered for testing. • Ten of the 51 eligible firefighters were randomly selected for the treadmill tests. • Treadmill 3.5 mph and 16% gradient.

11. Conclusions • All 10 firefighters studied on the treadmill overbreathed their respirators. • Facepiece fit was excellent in most firefighters. • Only one of the 51 firefighters fit for a large facepiece could potentially have had a respirator PF of less than 10,000.

12. Medical surveillance • Seattle Fire Department since 1988 • Voluntary for 1,108 uniformed firefighters • Annual pulmonary function tests including forced vital capacity (FVC), forced expiratory volume- 1 second (FEV1) and diffusing capacity of the lung to carbon monoxide (DLCO)

13. DLCO by exam year

14. Decline in DLCO: possible causes • Machine error • Changes in firefighter population (age, race, smoking, FEV1, etc.) • Smoke exposure or other workplace exposure

15. Instrument testing • Firefighters were tested on both the regular DLCO unit and a second similar unit • 22 paired measurements were compared • No statistically significant difference was found

16. Hospital testing • 11 of 18 firefighters with DLCO <70% were retested • No statistically significant difference in the measurements • 4 of the 11 firefighters were exercised tested, and 3 of 4 tests were normal

17. Firefighter characteristics Year 1989 1990 1991 1992 1993 1994 1995 1996 Age 39 38 37 37 35 35 34 34 Male (%) 94 94 94 93 91 91 92 90 Minority (%) 11 12 12 13 14 13 14 13 Smoker (%) 19 19 17 15 14 12 10 10 Annual fires 20 20 19 19 17 17 16 16 Respirator use (%): extinguish 76 78 77 78 78 77 77 78 entry/vent 69 71 69 70 70 70 70 70 standby 30 28 27 27 25 25 25 25 overhaul 47 48 46 48 48 49 50 50

18. DLCO Regression model (n = 812) Parameter Estimate Std Error p Intercept -6.448 4.168 0.1223 Age (years) -0.124 0.023 0.0001 Height (m) 19.956 2.362 0.0001 Female -4.966 0.694 0.0001 Minority -2.184 0.432 0.0001 FVC 2.400 0.200 0.0001 Pack-years -0.060 0.017 0.0005 Smoking -2.065 0.483 0.0001 AVEFIRE 0.050 0.015 0.0013

19. DLCO Regression model (continued) Parameter Estimate Std Error p Time -0.913 0.291 0.0017 Age*time 0.017 0.004 0.0001 Female*time 0.230 0.115 0.0467 FVC*time -0.111 0.035 0.0006 Smoking*time 0.241 0.075 0.0014 AVEFIRE*time -0.006 0.003 0.0333

20. DLCO Discussion • -1.02 ml/min/mmHg associated with year of measurement v. -0.006 ml/min/mmHg associated with number of fires fought. • Actual extent of smoke exposure could not be directly or quantitatively determined. • Is DLCO useful for medical surveillance?

21. Overhaul (OH) • Phase after the flames have been doused when firefighters (FF) search for and extinguish hidden sources of combustion • Usually no visible smoke • Firefighters often remove respirators • Recent study (Bolstad-Johnson et al., 2000) suggests potential for significant exposure

22. Methods-biomarkers • Baseline and 1 hour post-OH measurements • FVC and FEV1 • Serum Clara cell protein (CC16) • Surfactant associated protein A (SPA)

23. Methods-overhaul • Phoenix FF wore air purifying respirators (APR) • Tucson FF wore no respiratory protection • Monitored for smoke exposure during OH

24. Results-FF participants Tucson (n=25) Phoenix (n=26) Age 39.6  6.7 39.3  8.1 Male gender 24 (96%) 25 (96%) non-Hisp. White 15 (60%) 14 (54%) Hispanic 8 (32%) 11 (42%) Black 0 1 ( 4%) Other 2 ( 8%) 0 Current smoker 1 ( 4%) 1 ( 4%)

25. Results-smoke exposure (ppm) Analyte n* Tucson n* Phoenix Formaldehyde 21/22 0.11±0.18 19/19 0.26 ±0.25 Acetaldehyde 5/23 0.16±0.01 18/19 0.38±0.49 Respirable dust† 0/24 11/19 6.18±7.80 Benzene 0/23 10/20 0.56±0.47 HCl 6/23 0.21±0.11 9/19 0.89±0.62 H2SO4† 4/23 0.27±0.01 10/19 3.40±3.63 * Number of measurements exceeding LOD / number of samples collected † Measurements in mg/m3, all other values given in ppm

26. Results-smoke exposure (ppm) Analyte n Tucson n Phoenix Carbon monoxide 18 12.2±10.5 13 34.1±34.7 Nitrogen dioxide 18 0.003±0.005 13 0.008±0.007 Sulfur dioxide 18 0.45±0.40 13 1.52±1.42

27. Results-biomarkers Group n CC16* SP-A* n FVC (L) FEV1 (L) TFD 25 8.93.5 287144 19 5.420.72 4.100.62 TFD-OH 25 12.33.6† 306157 19 5.360.73 3.940.65 PFD 26 9.63.5 250117 26 5.440.68 4.220.51 PFD-OH 26 14.65.2†334141†265.290.74†4.090.56† * units g/L † p <0.01

28. Interleukins • IL-10 supresses inflammation • IL-8 and TNF- are pro-inflammatory • Relative to non-smokers, sputum IL-10 concentrations in healthy smokers are decreased 25% and smokers with COPD 75%

29. Sputum cytokines

30. Sputum IL-10

31. Discussion • Phoenix FF had significant reductions in spirometry and increase in lung permeability following OH • OH exposures greater in Phoenix • Use of APR did not protect against changes in biomarkers

32. Recommendations Either Use self-contained breathing apparatus during overhaul or Increase the time interval between extinguishment and start of overhaul, maximizing structure ventilation

33. References • Burgess JL and Crutchfield CD. Tucson fire fighter exposure to products of combustion: A risk assessment. Applied Occupational and Environmental Hygiene 1995; 10: 37-42. • Burgess JL and Crutchfield CD. Quantitative respirator fit tests of Tucson fire fighters and measurement of negative pressure excursions during exertion. Applied Occupational and Environmental Hygiene 1995; 10: 29-36. • Burgess JL, Brodkin CA, Daniell WE, Pappas GP, Keifer MC, Stover BD, Edland SD, Barnhart S. Longitudinal decline in measured firefighter single-breath diffusing capacity of carbon monoxide values: A respiratory surveillance dilemma. American Journal of Respiratory and Critical Care Medicine 1999;159:119-124. • Bolstad-Johnson DM, Burgess JL, Crutchfield CD, Storment SB, Gerkin RD. Characterization of firefighter exposures during fire overhaul. American IndustrialHygiene Association Journal 2000;61:636-641. • Burgess JL, Nanson CJ, Bolstad-Johnson DM, Gerkin R, Hysong TA, Lantz RC, Sherrill DL, Crutchfield CD, Quan SF, Bernard AM, Witten ML. Adverse respiratory effects following overhaul in firefighters. Journal of Occupational and Environmental Medicine 2001;43:467-473. • Burgess JL, Nanson CJ, Gerkin R, Witten ML, Hysong TA, Lantz RC. Rapid decline in sputum IL-10 concentration following occupational smoke exposure. InhalationToxicology 2002;14:133-140.