Impact of select PPE design elements and repeated laundering in firefighter protection from smoke exposure

Figures & data

Figure 1. Overhead and front view of Fireground Smoke Exposure prop with mannequin orientation (samples collected in the east exposure chamber only).

Figure 2. Study design and sample collection strategy.

Figure 3. Side-by-side comparison of zipper and hook & dee turnout jacket closures.

Table 1. Total PAH (μg/m³) and benzene (ppb) ambient east chamber air concentrations.

Analyte	Exposure Trial	N	Air median	Range	p-value^A
Total PAHs	New	2	285,500	277,000–294,000	0.0312
	10	2	225,500	213,000–238,000
	20	2	157,500	136,000–179,000
	40	3	70,700	40,000–125,000
Benzene	New	2	189,500	152,000–227,000	0.639
	10	1	187,000	N/A
	20	1	314,000	N/A
	40	1	199,000	N/A

^Ap-values calculated from ANOVA on the log of the ambient PAH and benzene air concentrations.

Table 2. Median total PAH concentration (μg/filter) on PTFE filters under jackets (chest). Ratios calculated using median ambient chamber air PAH concentrations are also provided in parentheses to estimate protection factors.

	Laundered							Decontaminated
	Hook			Zipper			Hook vs. Zipper	Zipper
Exposure Trial	N	Median Total PAH (Ratio^A)		N	Median Total PAH (Ratio^A)		p-value^B	N	Median Total PAH (Ratio)
New	3	6.28 (45,500)		2	7.07 (44,400)		0.037	1	7.23 (39,500)
10	3	15.6 (14,400)		3	2.01 (112,400)			3	4.46 (50,600)
20	2	11.5 (25,900)		3	3.63 (43,400)			3	7.34 (21,400)
40	1	7.68 (9,200)		3	7.35 (9,600)			3	5.53 (12,800)
Trend p-value^C		0.1			0.01				0.105

^ATo estimate the impact of repeated exposure and laundering on PPE protection factors, we calculated the ratio of median ambient chamber air PAH concentrations (Table 1) to median PAH levels on PTFE filters under jackets (chest region).

^Bp-value from multiple linear regression of the log-transformed ratios of PAHs deposited under jackets in the chest region to median ambient chamber air PAH concentrations by type of jacket closure, controlling for cleaning cycles/exposure trial

^Cp-value from multiple linear regression of log-transformed ratios vs. cleaning cycles/exposure trial, controlling for type of jacket closure

Table 3. Median total PAH concentration (μg/filter) on PTFE filters under laundered hoods. Ratios calculated using median ambient chamber air PAH concentrations are also provided in parentheses to estimate protection factors.

		Knit			Particulate-Blocking			Knit vs. Particulate-Blocking
Exposure Trial		N	Median Total PAH (Ratio^A)		N	Median Total PAH (Ratio^A)		p-value^B
New		3	26.3 (10,900)		3	16.2 (17,600)		0.003
10		3	18.3 (12,300)		3	13.1 (17,200)
20		3	17.8 (8,800)		3	11.4 (13,800)
40		3	13.0 (5,500)		3	6.65 (10,600)
Trend p-value^C			0.001			0.045

^ATo estimate the impact of repeated exposure and laundering on PPE protection factors, we calculated the ratio of median ambient chamber air PAH concentrations (Table 1) to median PAH levels on PTFE filters under hoods (neck region)

^Bp-value from multiple linear regression of the log-transformed ratios of PAHs deposited under jackets in the chest region to median ambient chamber air PAH concentrations by type of hood, controlling for cleaning cycles/exposure trial

^Cp-value from multiple linear regression of the log-transformed ratios vs. cleaning cycles/exposure trial, controlling for type of hood

Table 4. Median benzene concentration (ppb) under jackets. Ratios calculated using median ambient chamber air benzene concentrations are also provided in parentheses to calculate workplace protection factors (WPFs).

		Laundered								Decontaminated
		Hook			Zipper			Hook vs. Zipper		Zipper
Exposure Trial		N	Median Benzene (Ratio^A)		N	Median Benzene (Ratio^A)		p-value^B		N	Median Benzene (Ratio)
New		3	348,000 (0.54)		3	357,000 (0.53)		0.462		2	282,000 (0.7)
10		3	251,000 (0.74)		3	213,000 (0.88)				2	162,000 (1.16)
20		1	213,000 (1.47)		2	248,000 (1.29)				2	214,000 (1.48)
40		1	137,000 (1.45)		1	150,000 (1.32)				2	115,000 (1.73)
Trend p-value^C			0.017			0.003					0.008

^ATo estimate the impact of repeated exposure and laundering on PPE protection factors, we calculated the ratio of median ambient chamber air benzene concentrations (Table 1) to benzene under jackets (rib region)

^Bp-value from multiple linear regression of the log-transformed ratios of benzene under jackets in the chest region to median ambient chamber air benzene concentrations by type of jacket closure, controlling for cleaning cycles/exposure trial

^Cp-value from multiple linear regression of the log-transformed ratios vs. cleaning cycles/exposure trial, controlling for type of jacket closure