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
Smoke exposure

• Acrolein
• Benzene
• Carbon Monoxide
• Hydrogen chloride
• Hydrogen cyanide
• Nitrogen dioxide

• Particulates
• Polycyclic aromatic hydrocarbons (PAHs)
• Sulfur dioxide
• and thousands more

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
Fit-testing

• 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.

8
CNP Fit-tests for Tucson

• Mean Leak (cc/min) All () Large ()
• lt2.5 66 68
• 2.6-10 15 16
• 10.1-50 9 8
• 50.1-100 3 8
• 101-500 5 8
• gt500 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.

10

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 lt70 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

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DLCO Regression model (continued)

• Parameter Estimate Std Error p
• Time -0.913 0.291 0.0017
• Agetime 0.017 0.004 0.0001
• Femaletime 0.230 0.115 0.0467
• FVCtime -0.111 0.035 0.0006
• Smokingtime 0.241 0.075 0.0014
• AVEFIREtime -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 (n25) Phoenix (n26)
• 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 0.110.18 19/19 0.26 0.25
• Acetaldehyde 5/23 0.160.01 18/19 0.380.49
• Respirable dust 0/24 11/19 6.187.80
• Benzene 0/23 10/20 0.560.47
• HCl 6/23 0.210.11 9/19 0.890.62
• H2SO4 4/23 0.270.01 10/19 3.403.63
• 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 12.210.5 13 34.134.7
• Nitrogen dioxide 18 0.0030.005 13 0.0080.007
• Sulfur dioxide 18 0.450.40 13 1.521.42

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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 26 5.29?0.74 4.09?0.
  56
• units ?g/L
• p lt0.01

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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 1999159119-124.
• Bolstad-Johnson DM, Burgess JL, Crutchfield CD,
  Storment SB, Gerkin RD. Characterization of
  firefighter exposures during fire overhaul.
  American Industrial Hygiene Association Journal
  200061636-641.
• 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 200143467-473.
• Burgess JL, Nanson CJ, Gerkin R, Witten ML,
  Hysong TA, Lantz RC. Rapid decline in sputum
  IL-10 concentration following occupational smoke
  exposure. Inhalation Toxicology 200214133-140.