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

Smoke exposure

Acrolein Benzene Carbon Monoxide Hydrogen chloride Hydrogen cyanide Nitrogen dioxide

Particulates Polycyclic aromatic

hydrocarbons (PAHs) Sulfur dioxide and thousands more

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

Phases of firefighting

Entinguishment (knockdown) Entry/ventilation Rescue Support/standby Overhaul

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?

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.

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.

CNP Fit-tests for Tucson*

Mean Leak (cc/min) All (%) Large (%)<2.5 66 682.6-10 15 1610.1-50 9 850.1-100 3 8101-500 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

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.

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.

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)

DLCO by exam year

80

90

100

110

1989 1990 1991 1992 1993 1994 1995 1996

% P

redi

cted

DL

CO

(Cra

po)

Non-smokers

Smokers

Decline in DLCO: possible causes

Machine error Changes in firefighter population (age,

race, smoking, FEV1, etc.)

Smoke exposure or other workplace exposure

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

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

Firefighter characteristicsYear 1989 1990 1991 1992 1993 1994 1995

1996Age 39 38 37 37 35 35 34 34Male (%) 94 94 94 93 91 91 92 90Minority (%) 11 12 12 13 14 13 14 13Smoker (%) 19 19 17 15 14 12 10 10Annual fires 20 20 19 19 17 17 16 16Respirator 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

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

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

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?

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

Methods-biomarkers

Baseline and 1 hour post-OH measurements

FVC and FEV1

Serum Clara cell protein (CC16) Surfactant associated protein A (SPA)

Methods-overhaul

Phoenix FF wore air purifying respirators (APR)

Tucson FF wore no respiratory protection Monitored for smoke exposure during OH

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%)

Results-smoke exposure (ppm)

Analyte n* Tucson n* Phoenix

Formaldehyde 21/22 0.11±0.1819/190.26 ±0.25

Acetaldehyde 5/23 0.16±0.0118/190.38±0.49

Respirable dust† 0/24 11/196.18±7.80

Benzene 0/23 10/200.56±0.47

HCl 6/23 0.21±0.119/190.89±0.62

H2SO4†

4/23 0.27±0.0110/193.40±3.63* Number of measurements exceeding LOD / number of samples collected† Measurements in mg/m3, all other values given in ppm

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

Results-biomarkers

Group n CC16* SP-A* n FVC (L) FEV1 (L)

TFD 25 8.93.5 287144 19 5.420.72 4.100.62

TFD-OH 2512.33.6† 306157 19 5.360.73 3.940.65

PFD 26 9.63.5 250117 26 5.440.68 4.220.51

PFD-OH 2614.65.2†334141† 265.290.74†4.090.56†

* units g/L† p <0.01

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%

Sputum cytokines

Group TNF- IL-8 IL-10

PFD 9.812.4 600795 69.272.5

PFD-OH 10.612.0 768953 13.725.2*

p<0.01

Firefighters with rapid rates of longitudinaldecline in lung function had a 27% lower sputumIL-10 concentration than slow decliners (p=0.59)

Sputum IL-10

0

20

40

60

80

100

120

140

160

180

200

baseline overhaul

IL-1

0 co

ncen

trat

ion

(pg/

L)

.

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

Recommendations

EitherUse self-contained breathing apparatus

during overhaulor

Increase the time interval between extinguishment and start of overhaul,

maximizing structure ventilation

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 Industrial Hygiene 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. Inhalation Toxicology 2002;14:133-140.