Assessment of spray polyurethane foam worker exposure to organophosphate flame retardants through measures in air, hand wipes, and urine

Figures & data

Figure 1. Photos of helper (left) and sprayer (right). The helpers cut and bundled freshly sprayed foam, sometimes without coveralls or gloves. The sprayer usually wore partial coverall, gloves, and an air-supplied respirator for protection from overspray.

Table 1. Characteristics of participating spray polyurethane foam workers.

Characteristic	Frequency (%)
Gender
Male	29 (100)
Race
White	26 (89.7)
Black	3 (10.3)
Ethnicity
Hispanic or Latino	1 (3.45)
Not Hispanic or Latino	28 (96.6)
Age (Years)	Mean ± SD = 29.8 ± 8.06
Body Mass Index (kg/m^2)	Mean ± SD = 26.1 ± 4.51
Length of Time Working in the Industry (Years)	Mean ± SD = 3.47 ± 3.84
Last Shift Worked
Yesterday	19 (65.5)
2 days ago	2 (6.90)
3 days ago	5 (17.2)
4 or more	3 (10.3)
Job Position
Sprayer	13 (44.8)
Helper	16 (55.2)
Gloves Worn during Spraying	Sprayer	Helper
Yes	10	5
Intermittent	3	6
No	0	5
Respirator Worn during Spraying	Sprayer	Helper
None	1	7
Half-Face Air-Purifying	4	6
Full-Face Air-Purifying	2	1
Air-Supplied	6	2

Table 2. Flame retardant metabolites quantified in urine samples.

Analyte	Parent Chemical
Diphenyl phosphate (DPhP)	Triphenyl phosphate (TPP or TPhP), Isopropylphenyl diphenyl phosphate t-Butylphenyl diphenyl phosphate 2-Ethylhexyl diphenyl phosphate
Bis(1,3-dichloro-2-propyl) phosphate (BDCPP)	Tris(1,3-dichloro-2-propyl) phosphate (TDCPP)
Di-p-cresyl phosphate (DpCP)	Tri-p-cresyl phosphate (TpCP)
Bis(1-chloro-2-propyl) phosphate (BCPP)	Tris(1-chloro-2-propyl) phosphate (TCPP, TCIPP)
Dibutyl phosphate (DBP or DBuP)	Tributyl phosphate (TBP or TBuP)
Dibenzyl phosphate (DBzP)	Tribenzyl phosphate (TBzP)
2,3,4,5-Tetrabromobenzoic acid (TBBA)	2-Ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB)
Bis(2-chloroethyl) phosphate (BCEtP)	Tris(2-chloroethyl) phosphate (TCEP)
Di-o-cresyl phosphate (DoCP)	Tri-o-cresyl phosphate (ToCP)

Figure 2. TCPP air concentrations by job position (N = 29). The box represents the interquartile range, the line in each box represents the median, and the triangle represents the GM. The upper whisker represents the far upper fence 1.5 IQR above the 75th percentile, the lower whisker represents the lower fence 1.5 IQR below the 25th percentile, and the circles represent outliers.

Table 3. TCPP hand wipe concentrations* (ng/sample) and comparisons.

Job Position	Sample Collection	N	Median	GM (GSD)	25th–75th Percentiles	Range	P-value
Sprayer	Pre	13	81,600	46,000 (4.92)	10,100–195,000	3,270–384,000	0.512^†
	Post	13	61,200	62,600 (3.02)	34,300–161,000	11,100–322,000
Helper	Pre	16	30,000	27,300 (3.16)	10,000–80,000	3,550–166,000	<0.001^†
	Post	16	109,000	106,000 (2.05)	59,300–189,000	30,200–315,000
Total	Pre	29	35,400	34,500 (3.92)	10,100–106,000	3,270–384,000	0.004^†
	Post	29	88,700	83,500 (2.54)	40,400–166,000	11,100–322,000
Gloves							0.280^‡
No
Sprayer	Post	0	^§	^§	^§	^§
Helper	Post	5	92,900	107,000 (2.00)	60,800–138,000	57,800–311,000
Yes
Sprayer	Post	10	73,500	75,000 (3.02)	34,300–215,000	11,100–322,000
Helper	Post	5	88,700	88,900 (1.51)	78,300–126,000	47,900–132,000
Intermittent
Sprayer	Post	3	36,800	^§	^§	11,500–95,100
Helper	Post	6	189,000	121,000 (2.68)	40,400–230,000	30,200–315,000
Handwashing							0.172^‡
Yes
Sprayer	Post	5	34,300	39,800 (3.82)	11,500–95,100	11,100–240,000
Helper	Post	8	129,000	119,000 (1.48)	90,800–152,000	60,800–211,000
No
Sprayer	Post	8	73,500	83,000 (2.48)	37,700–188,000	27,100–322,000
Helper	Post	8	68,000	93,700 (2.61)	44,100–270,000	30,200–315,000

TCPP: Tris(1-chloro-2-propyl) phosphate; GM: geometric mean; GSD: geometric standard deviation.

^*All hand-wipe samples were above limit of detection (LOD) for TCPP. LODs were 5, 10, or 15.6 ng/sample.

^†Paired t-test was utilized to compare pre- and post-shift concentrations by job positions and for all workers.

^‡One-way analysis of variance (ANOVA) and Student’s t-test were utilized for comparisons for covariates, gloves (no, yes, and intermittent) and handwashing (yes, no), respectively.

^§Not enough samples to calculate central tendencies.

Table 4. Urine sampling concentrations* using paired t-test (μg/g cr).

Analyte	Sample Collection	Job Position	N	Median	GM (GSD)	25th–75th Percentiles	Range	P-value
BCPP*
	Pre	Sprayer	13	38.60	39.70 (3.92)	17.00–57.40	5.390–830.000	0.013
	Post	Sprayer	13	47.10	70.40 (3.55)	31.90–99.10	17.000–1,620.000
	Pre	Helper	16	6.91	7.86 (3.29)	2.81–15.60	1.790–82.400	0.009
	Post	Helper	16	29.80	19.90 (3.12)	8.94–47.70	1.780–88.000
BDCPP*
	Pre	Sprayer	13	2.60	2.81 (2.95)	1.84–4.61	0.227–25.700	0.856
	Post	Sprayer	13	2.35	2.95 (2.90)	1.79–6.31	0.321–16.800
	Pre	Helper	16	2.58	2.43 (1.87)	1.80–3.55	0.660–7.750	0.938
	Post	Helper	16	2.46	2.66 (1.77)	1.89–4.00	0.741–7.310

GM: geometric mean; GSD: geometric standard deviation; BCPP: bis(1-chloro-2-propyl) phosphate; BDCPP: bis (1,3-dichloro-2-propyl) phosphate.

*Limit of detection (LOD) for BCPP was 0.10 µg/L and for BDCPP was 0.11 µg/L. All samples were above the LOD.

Table 5. Univariate analysis results using a mixed model with company as a random effect.

Covariate*	BCPP Urine Post Day Two (N = 29)
	Estimate (SE)	P-value
Job Position
Sprayer	Ref
Helper	−1.519 (0.399)	<0.001
Respirator Use
Air-Supplied	Ref
None	−1.958 (0.587)	0.003
Half-face Air-Purifying	−0.746 (0.582)	0.215
Full-face Air-Purifying	−0.558 (0.748)	0.465
Hand Wipe Pre-Shift	0.435 (0.163)	0.014
Hours Since Last Shift	−0.020 (0.008)	0.029
BCPP Urine Pre-Shift	0.674 (0.107)	<0.001
TWA Air	0.671 (0.171)	<0.001

BCPP: bis(1-chloro-2-propyl) phosphate; Ref: reference group; SE: standard error.

* These variables were not significant: minutes sprayed (p = 0.734), pump minutes (p = 0.754), hands washed (p = 0.819), hand wipe post (p = 0.140), glove usage (p = 0.175), BMI (p = 0.348), length of time working in industry (p = 0.413), race (p = 0.397), age (p = 0.348), and hand wipe difference (p = 0.212).

Table 6. Multivariate analysis results using a mixed model with company as a random effect.

	BCPP Urine Post Day Two (N = 29)
Covariate	Estimate (SE)	P-value
TWA Air	0.461 (0.146)	0.005
Hand Wipe Pre-Shift	0.419 (0.128)	0.004
Hand Wipe Post-Shift	0.405 (0.191)	0.048
Job Position
Sprayer	Ref
Helper	−0.828 (0.376)	0.041

BCPP: bis(1-chloro-2-propyl) phosphate; Ref: reference group.

Figure 3. BCPP and BDCPP creatinine-adjusted urine concentrations by position and time compared to the adult male general population (N = 29). The box represents the interquartile range, the line in each box represents the median, and the black triangle represents the GM. The upper whisker represents the far upper fence 1.5 IQR above 75th percentile, the lower whisker represents the lower fence 1.5 IQR below the 25th percentile, and the circles represent outliers. *The GM and 95th% CI for BCPP and BDCPP were general population averages calculated using the National Health and Nutrition Examination Survey 2013–2014 (men above age 18).