Reducing Transdermal Uptake of Semivolatile Plasticizers from Indoor Environments: A Clothing Intervention.

Models and laboratory studies suggest that everyday clothing influences the transdermal uptake of semivolatile organic compounds, including phthalate plasticizers, from indoor environments. However, this effect has not been documented in environmental exposure settings. In this pilot study, we quantified daily excretion of 17 urinary metabolites (µg/day) for phthalates and phthalate alternatives in nine participants during 5 days. On Day 0, baseline daily excretion was determined in participants' urine. Starting on Day 1, participants refrained from eating phthalate-heavy foods and using personal care products. On Days 3 and 4, participants wore precleaned clothing as an exposure intervention. We observed a reduction in the daily excretion of phthalates during the intervention; mono-n-butyl phthalate, monoisobutyl phthalate (MiBP), and monobenzyl phthalate were significantly reduced by 35, 38, and 56%, respectively. Summed metabolites of di(2-ethylhexyl)phthalate (DEHP) were also reduced (27%; not statistically significant). A similar reduction among phthalate alternatives was not observed. The daily excretion of MiBP during the nonintervention period strongly correlated with indoor air concentrations of diisobutyl phthalate (DiBP), suggesting that inhalation and transdermal uptake of DiBP from the air in homes are dominant exposure pathways. The results indicate that precleaned clothing can significantly reduce environmental exposure to phthalates and phthalate alternatives.

Occupational exposure to PFAS: Research and protection needed.

Per- and polyfluoroalkyl substances (PFAS) have been used in a variety of consumer and industrial applications. PFAS are associated with numerous detrimental health effects, but workplace exposure to PFAS has only been studied in a small number of occupations. More research is needed to fully understand how workers may be exposed to PFAS and what health effects this may cause.

Occupational exposures to airborne per- and polyfluoroalkyl substances (PFAS)-A review.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) are a group of synthetically-made chemicals with diverse functional properties that have become ubiquitous in our environment because of their widespread use. PFAS exposure has been associated with adverse health effects, and it is therefore vital to know how exposure may occur. Many studies have focused on environmental exposure from drinking water, but there is a paucity of data on inhalation exposure, especially in occupational settings. METHODS: In this study, through a comprehensive literature search, measured airborne (i.e., aerosols, volatiles, and dust) inhalation exposure and area levels were compiled for various occupations to compare reported levels of PFAS exposure. Airborne PFAS levels measured in various occupations such as ski waxing, textile manufacturing, firefighting, and floor waxing were analyzed and compared. RESULTS: Results of this review demonstrate that workers experience varying levels of PFAS exposure contingent on the workplace and industry and the work tasks performed within the workplace. Out of all occupations, ski waxing exhibited the highest total PFAS airborne concentrations when compared to all other reported occupational and residential exposures. CONCLUSIONS: Further research is recommended to estimate the risk of PFAS exposures in the occupations reviewed and to identify other potential occupations at risk of PFAS exposure. In addition, informed recommendations to implement safety measures ought to be developed to protect workers from adverse health effects.

Occupational exposure and serum levels of per- and polyfluoroalkyl substances (PFAS): A review.

BACKGROUND: Per- and polyfluoroalkyl substances, or PFAS, are a class of chemicals used in nearly all sectors of industry and many consumer products. Their resistance to degradation, however, means that PFAS are ubiquitous in the environment and bioaccumulate. PFAS exposure has also been linked to a variety of adverse health effects. Occupational PFAS exposure is of particular concern as research on PFAS exposure in worker populations has historically been limited and generally restricted to fluorochemical plant workers involved in PFAS production. METHODS: A comprehensive review of peer-reviewed scientific literature was conducted to investigate which worker populations may experience occupational exposure to PFAS. Serum PFAS levels reported in various occupations were analyzed and compared to serum PFAS levels published on the general public exposed to PFAS-contaminated drinking water and the study population of the National Health and Nutrition Examination Survey (NHANES). RESULTS: Our analysis indicates that professional ski waxers and firefighters may be exposed to several different PFAS at levels often similar to or higher than levels among fluorochemical plant workers and individuals in communities with PFAS-contaminated drinking water, and higher than levels in the general public. PFAS serum level data on other occupations were largely absent. CONCLUSIONS: Results highlight a need for additional research on occupational PFAS exposures and concomitant environmental exposures in these populations. Research on exposure levels in occupations and industries known or suspected to utilize PFAS is critically needed to foster informed recommendations for exposure mitigation measures to protect workers from adverse health effects of PFAS exposure.

Lung and extrathoracic cancer incidence among underground uranium miners exposed to radon progeny in the Príbram region of the Czech Republic: a case-cohort study.

OBJECTIVES: Radon is carcinogenic, but more studies are needed to understand relationships with lung cancer and extrathoracic cancers at low exposures. There are few studies evaluating associations with cancer incidence or assessing the modifying effects of smoking. METHODS: We conducted a case-cohort study with 16 434 underground uranium miners in the Czech Republic with cancer incidence follow-up 1977-1996. Associations between radon exposure and lung cancer, and extrathoracic cancer, were estimated with linear excess relative rate (ERR) models. We examined potential modifying effects of smoking, time since exposure and exposure rate. RESULTS: Under a simple ERR model, assuming a 5-year exposure lag, the estimated ERR of lung cancer per 100 working level months (WLM) was 0.54 (95% CI 0.33 to 0.83) and the estimated ERR of extrathoracic cancer per 100 WLM was 0.07 (95% CI -0.17 to 0.72). Most lung cancer cases were observed among smokers (82%), and the estimated ERR of lung cancer per 100 WLM was larger among smokers (ERR/100 WLM=1.35; 95% CI 0.84 to 2.15) than among never smokers (ERR/100 WLM=0.12; 95% CI -0.05 to 0.49). Among smokers, the estimated ERR of lung cancer per 100 WLM decreased with time since exposure from 3.07 (95% CI -0.04 to 10.32) in the period 5-14 years after exposure to 1.05 (95% CI 0.49 to 1.87) in the period 25+ years after exposure. CONCLUSIONS: We observed positive associations between cumulative radon exposure and lung cancer, consistent with prior studies. We observed a positive association between cumulative radon exposure and extrathoracic cancers, although the estimates were small. There was evidence that the association between radon and lung cancer was modified by smoking in a multiplicative or super-multiplicative fashion.

Radon and cancer mortality among underground uranium miners in the Príbram region of the Czech Republic.

BACKGROUND: This study aims to estimate the association between radon and site-specific cancer mortality among a large contemporary cohort of male uranium miners. METHODS: Annual occupational radon exposure was estimated based on a worker's duration of underground mining in a year and estimates of potential alpha energy of radon progeny in their location of work. Cancer mortality over the period 1977-1992 was ascertained for a cohort of 16 434 male underground uranium miners employed in the Czech Republic between 1946 and 1992. Poisson regression was used to estimate relationships between cumulative radiation exposure (in working level months [WLM]) and site-specific cancer mortality. RESULTS: Radon is positively associated with lung cancer mortality (excess relative rate [ERR] per 100 WLM = 0.2; 95% confidence interval [CI]: 0.10, 0.37). The best fit of the dose-response relationship between radon and lung cancer mortality was linear and estimates of radon-lung cancer associations varied by windows of time-since-exposure. Positive associations between radon and several types of cancer other than lung cancer were identified, notably chronic lymphocytic leukemia (CLL) (ERR/100 WLM = 0.24; 95% CI: [not determined [ND], 5.10]) and extrathoracic cancer (ERR/100 WLM = 0.12; 95% CI: [ND, 0.69]). We observed no associations between radon and stomach cancer, nor between radon and several hematopoietic cancer subtypes. CONCLUSIONS: This study confirms the established radon-lung cancer association and suggests that radon may also be associated with other types of cancer mortality. Further investigations of extrathoracic and CLL cancer, with the aim of obtaining more precise estimates, are warranted to understand associations between radon and cancers other than lung.

Inorganic Arsenic as an Endocrine Disruptor: Modulation of the Glucocorticoid Receptor Pathway in Placental Cells via CpG Methylation.

Prenatal exposure to inorganic arsenic (iAs) has been associated with adverse developmental and reproductive outcomes. These outcomes may be tied to altered functionality of nuclear transcription factors such as the glucocorticoid receptor (GR) in the placenta and associated gene expression. The GR pathway is integral for proper fetal and placental development, and perturbations in this pathway may underlie observed associations between prenatal iAs exposure and adverse birth outcomes. We therefore set out to investigate whether iAs modulates the GR signaling pathway in placental cells. JEG-3 trophoblasts were exposed to environmentally-relevant doses of iAs, and mRNA expression assessed. To examine the links between iAs exposure, the GR signaling pathway, and epigenetic modification, DNA methylation levels were also quantified. Treatment with iAs altered the expression of 12 GR-genes that play a role in fetal and placental development. Furthermore, at a gene-specific level, mRNA abundance was associated with changes in DNA methylation patterning in JEG-3 cells, suggesting that the effects of iAs are mediated by epigenetic mechanisms. The identified target genes have been associated with prenatal iAs exposure, placental physiology, and fetal development. This study provides further evidence for iAs as an endocrine disruptor and provides insight as to the mechanisms by which prenatal iAs exposure may induce adverse birth outcomes.

Mortality and cancer incidence among underground uranium miners in the Czech Republic 1977-1992.

OBJECTIVES: Uranium miners in Príbram, Czech Republic were exposed to low and moderate levels of radon gas and other hazards. It is unknown whether these hazards increase the risk of mortality or cancer incidence when compared with the general Czech population. METHODS: A cohort of 16 434 male underground miners employed underground for at least 1 year between 1946 and 1976, and alive and residing in the Czech Republic in 1977, were followed for mortality and cancer incidence through 1992. We compared observed deaths and cancer incidence to expectation based on Czech rates. Standardised mortality ratios (SMRs), standardised incidence ratios (SIRs) and causal mortality ratios were calculated. RESULTS: Underground workers in the Príbram mines had higher rates of death than expected due to all causes (SMR=1.23, 95% CI 1.20 to 1.27), all cancers (SMR=1.52, 95% CI 1.44 to 1.60), lung cancer (SMR=2.12, 95% CI 1.96 to 2.28) and extrathoracic cancer (SMR=1.41, 95% CI 1.15 to 1.77). Similar excess was observed in cancer incidence analyses, with the addition of stomach cancer (SIR=1.37, 95% CI 1.11 to 1.63), liver cancer (SIR=1.70, 95% CI 1.16 to 2.25) and rectal cancer (SIR=1.41, 95% CI 1.16 to 1.66). The SIR was elevated for all leukaemias (SIR=1.51, 95% CI 1.08 to 2.07) and for lymphatic and haematopoietic cancers combined (SIR=1.31, 95% CI 1.05 to 1.61), but results for specific subtypes were imprecise. Deaths due to hazardous mining conditions resulted in 0.33 person-years of life lost per miner. CONCLUSIONS: Occupational exposure to the Príbram mines resulted in excess cancers at several sites, including sites previously linked to radon and uranium exposure. Incidence analyses showed relative excess of several additional cancer subtypes.

Effective Message Elements for Disclosures About Chemicals in Cigarette Smoke.

Introduction: Cigarette smoke contains at least 93 chemicals or "constituents" that the Food and Drug Administration has identified as harmful and potentially harmful constituents to human health. Our study sought to identify which constituent disclosure message elements are most effective in discouraging people from smoking. Methods: Three hundred eighty eight current smokers aged 18 and older completed an online survey in February 2015. We randomized participants to respond to one of two sets of 13 toxic products that contain cigarette constituents and 25 health effects associated with cigarette constituents. Results: Products that elicited the most discouragement were those with lower chances of exposure (e.g., explosives), followed by products with possible exposure (e.g., rat poison), and products with a high likelihood of exposure (e.g., floor cleaner). Awareness of toxic products that constituents are found in (p < .001) and low exposure products (p < .001) were associated with higher discouragement. Health effects that people had heard are caused by cigarette smoke constituents elicited higher discouragement from smoking cigarettes (p < .001). Cancer was associated with higher discouragement relative to respiratory, cardiovascular, and reproductive health effects (all p < .001). Conclusions: Cigarette smoke constituent messages may be more effective at discouraging smoking if they include information about carcinogenic health effects (e.g., mouth cancer and lung tumors) and low exposure toxic products (e.g., explosives and radioactive material) as message elements. Implications: Our study identified health effects and toxic products, especially cancers and rarely encountered toxic products, that may discourage smoking when included in disclosure messages. By constructing messages that communicate the harms associated with tobacco use by contextualizing those harms in terms of specific constituents, tobacco education messaging efforts may be increasingly successful.

Feasibility of Implementing a Total Worker Health® Intervention During the COVID-19 Pandemic in Small and Medium Businesses : Results From the Carolina PROSPER Study.

OBJECTIVE: In response to the COVID-19 pandemic's disruptive effect on employers and workers, an interdisciplinary team launched the Carolina Promoting Safe Practices for Employees' Return study to assess the feasibility of providing tailored technical assistance to small and medium North Carolina businesses using a Total Worker Health (TWH) ® approach. METHODS: Feasibility of the approach was assessed via surveys and interviews of business representatives from four participating businesses ranging in size from 3 to 110 employees. RESULTS: The TWH approach is feasible, that is, in demand, practical, and acceptable to protect and promote worker safety, health, and well-being. Potential challenges include implementation cost, difficulty engaging all employees, and difficulty accessing tailored health and safety materials in a timely manner. CONCLUSIONS: Additional refinement and testing of the TWH approach postpandemic with more worksites is warranted.

Estimated burden of disease attributable to selected occupational exposures in the United Arab Emirates.

BACKGROUND: As part of an effort to strengthen occupational safety and health programs, the United Arab Emirates (UAE) commissioned a study to estimate the burden of disease attributable to occupational exposure to carcinogens, particulate matter, and noise. METHODS: We developed an innovative simulation model to estimate the occupational disease burden and facilitate future assessments as more field-based quantitative data become available. RESULTS: We determined that, in 2008, an estimated 46 deaths (95% CI: 27-71) and 17,000 health-care facility visits (95% CI: 16,000-18,000), along with 4,500 cases of noise-induced hearing loss, were attributable to the occupational risk factors covered in this study. Lung cancer and leukemia were associated with the highest number of deaths (38), whereas asthma and chronic obstructive pulmonary disease contributed most to the health-care facility visits (nearly 16,900). The highest estimated occupational disease burden is in construction. CONCLUSION: These results will help the UAE to institute new policies for environment, health, and safety management.

Occupational silica exposure and chronic kidney disease.

INTRODUCTION: Occupational exposure to silica may be associated with chronic kidney disease (CKD). Most studies have been conducted in occupational cohorts with high levels of exposure but small numbers of cases. We analyzed data from a population-based case-control study of occupational silica exposure and CKD. METHODS: Cases were hospital patients with newly diagnosed CKD, and community controls were selected using random digit dialing and frequency matched by age, gender, race, and proximity to the hospital. Silica exposure estimates were assigned by industrial hygiene review of lifetime job history data and weighted for certainty and intensity. Conditional logistic regression was used to estimate the odds ratios (ORs) for CKD conditioned on demographic, lifestyle, and clinical variables. RESULTS: The mean age of participants was 63 years (range 30-83 years); 59% were male and 55% were white. Any silica exposure (compared with none) was associated with a 40% increased risk of CKD [OR = 1.40, 95% confidence interval (CI): 1.04, 1.89] in a multivariable adjusted model. The mean cumulative duration of silica exposure was significantly higher in exposed cases than in exposed controls (33.4 vs. 24.8 years, respectively). Overall, compared with nonexposed participants, the ORs (95% CI) for those below and above the median duration of silica exposure were 1.20 (0.77, 1.86) and 1.76 (1.14, 2.71), respectively. CONCLUSIONS: We found a positive relationship between occupational silica exposure and CKD. A dose-response trend of increasing CKD risk with increasing duration of silica exposure was observed and was particularly strong among nonwhites.

Penetration patterns of monomeric and polymeric 1,6-hexamethylene diisocyanate monomer in human skin.

We investigated penetration patterns of monomeric and polymeric 1,6-hexamethylene diisocyanate (HDI), experimentally and as part of commercial products, in excised full-thickness human skin at 5, 10, 30, or 60 min after exposure. We observed that both monomeric and polymeric HDI were readily absorbed into the skin and that the clearcoat composition affects the penetration rate of the individual isocyanates. The short-term absorption rates for HDI monomer, biuret, and isocyanurate were determined and used to estimate the exposure time required to reach a body burden equal to the American Conference of Governmental Industrial Hygienists (ACGIH) inhalation threshold limit value (TLV) or Oregon State occupational exposure limit (OEL). Oregon is the only government entity in the United States to promulgate a short-term exposure limit (STEL) for HDI-based polyisocyanates biuret and isocyanurate. Based on these absorption rates for a slow-drying clearcoat after 10 min (1.33 µg cm(-2) h(-1)) or 60 min (0.219 µg cm(-2) h(-1)), we calculated that 6.5 and 40 min dermal exposure, respectively, is required to achieve a dose of HDI equivalent to the ACGIH TLV. For biuret, the time to achieve a dose equivalent to the Oregon OEL for slow-drying clearcoat was much shorter (<31 min) than that for fast-drying clearcoat (618 min). Isocyanurate had the shortest skin absorption times regardless of clearcoat formulation (14 s-1.7 min). These results indicate that the dose received through dermal exposure to HDI-containing clearcoats has a significant potential to exceed the dose equivalent to that received through inhalation exposure at established regulatory limits. A critical need exists to monitor dermal exposure quantitatively in exposed workers, to use proper protective equipment to reduce dermal exposure, and to re-evaluate regulatory exposure limits for isocyanates.

Airborne isocyanate exposures in the collision repair industry and a comparison to occupational exposure limits.

Isocyanate exposure was evaluated in 33 spray painters from 25 Washington State autobody shops. Personal breathing zone samples (n = 228) were analyzed for isophorone diisocyanate (IPDI) monomer, 1,6-hexamethylene diisocyanate (HDI) monomer, IPDI polyisocyanate, and three polyisocyanate forms of HDI. The objective was to describe exposures to isocyanates while spray painting, compare them with short-term exposure limits (STELs), and describe the isocyanate composition in the samples. The composition of polyisocyanates (IPDI and HDI) in the samples varied greatly, with maximum amounts ranging from up to 58% for HDI biuret to 96% for HDI isocyanurate. There was a significant inverse relationship between the percentage composition of HDI isocyanurate to IPDI and to HDI uretdione. Two 15-min STELs were compared: (1) Oregon's Occupational Safety and Health Administration (OR-OSHA) STEL of 1000 µg/m(3) for HDI polyisocyanate, and (2) the United Kingdom's Health and Safety Executive (UK-HSE) STEL of 70 µg NCO/m(3) for all isocyanates. Eighty percent of samples containing HDI polyisocyanate exceeded the OR-OSHA STEL while 98% of samples exceeded the UK-HSE STEL. The majority of painters (67%) wore half-face air-purifying respirators while spray painting. Using the OR-OSHA and the UK-HSE STELs as benchmarks, 21% and 67% of painters, respectively, had at least one exposure that exceeded the respirator's OSHA-assigned protection factor. A critical review of the STELs revealed the following limitations: (1) the OR-OSHA STEL does not include all polyisocyanates, and (2) the UK-HSE STEL is derived from monomeric isocyanates, whereas the species present in typical spray coatings are polyisocyanates. In conclusion, the variable mixtures of isocyanates used by autobody painters suggest that an occupational exposure limit is required that includes all polyisocyanates. Despite the limitations of the STELs, we determined that a respirator with an assigned protection factor of 25 or greater is required to protect against isocyanate exposures during spray painting. Consequently, half-face air-purifying respirators, which are most commonly used and have an assigned protection factor of 10, do not afford adequate respiratory protection.

The genetics of occupational asthma development among workers exposed to diisocyanates: A systematic literature review with meta-analysis.

Diisocyanates are widely used compounds that pose a safety concern for workers in occupations within the spray-paint, spray-foam insulation, and furniture varnish industries. Epidemiological studies show that only a subset of workers exposed to diisocyanates develop diisocyanate-induced occupational asthma (diisocyanate asthma, DA), indicating that genetic susceptibility may play a role. The purpose of this systematic literature review was to compile and meta-analyze the reported data on genetic susceptibility markers for DA. Three databases (Embase, Pubmed, and Scopus) were searched and 169 non-duplicate publications were identified, of which 22 relevant occupational studies were included in this review. Researchers reported prevalence odds ratios (PORs) for 943 comparisons in 82 different genes/serotypes. Protein network functions for the DA-associated genes from this review include: antigen processing, lymphocyte activation, cytokine production regulation, and response to oxidative stress. Meta-analysis of comparisons between workers with DA and controls was conducted for 23 genetic markers within: CTNNA3, GSTM1, GSTP1, GSTT1, HLA-C, HLA-DQB1, HLA-DR1, HLA-DR3, HLA-DR4, HLA-DR7, and HLA-DR8. These genes code for proteins that are involved in cell-cell adhesions (CTNNA3), glutathione conjugation for xenobiotic metabolism (GST gene family), and immune system response (HLA gene family). The most compelling pooled PORs were for two studies on CTNNA3 (increased DA risk: rs10762058 GG, rs7088181 GG, rs4378283 TT; PORs 4.38-4.97) and three studies on HLA-DR1 (decreased DA risk, POR 0.24). Bioinformatics of the predicted protein pathways for DA shows overlap with biomarker-associated pathways in workers before development of asthma, suggesting overlap in toxicokinetic and toxicodynamic pathways of diisocyanates. The control groups were also compared against each other and differences were negligible. Suggestions for improving future research are also presented. Of the highest importance, the literature was found to be profoundly publication-biased, in which researchers need to report the data for all studied markers regardless of the statistical significance level. We demonstrate the utility of evaluating the overlap in predicted protein pathway functions for identifying more consistency across the reported literature including for asthma research, biomarker research, and in vitro studies. This will serve as an important resource for researchers to use when generating new hypothesis-driven research about diisocyanate toxicology.

Hemoglobin adducts in workers exposed to 1,6-hexamethylene diisocyanate.

We investigated the utility of 1,6-hexamethylene diamine (HDA) hemoglobin adducts as biomarkers of exposure to 1,6-hexamethylene diisocyanate (HDI) monomer. Blood samples from 15 spray painters applying HDI-containing paint were analyzed for hemoglobin HDA (HDA-Hb) and N-acetyl-1,6-hexamethylene diamine (monoacetyl-HDA-Hb) by GC-MS. HDA-Hb was detected in the majority of workers (≤1.2-37 ng/g Hb), whereas monoacetyl-HDA-Hb was detected in one worker (0.06 ng/g Hb). The stronger, positive association between HDA-Hb and cumulative HDI exposure (r(2) = 0.3, p < 0.06) than same day exposure (p ≥ 0.13) indicates long-term elimination kinetics for HDA-Hb adducts. This association demonstrates the suitability of HDA-Hb adducts for further validation as a biomarker of HDI exposure.

The utility of naphthyl-keratin adducts as biomarkers for jet-fuel exposure.

We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p = 0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+-) genotypes were associated with a decrease in urine naphthalene level (p < 0.0001). The NKA show great promise as biomarkers for dermal exposure to naphthalene. Further studies are warranted to characterize the relationship between NKA, other exposure biomarkers, and/or biomarkers of biological effects due to naphthalene and/or PAH exposure.

Factors affecting variability in the urinary biomarker 1,6-hexamethylene diamine in workers exposed to 1,6-hexamethylene diisocyanate.

Although urinary 1,6-hexamethylene diamine (HDA) is a useful biomarker of exposure to 1,6-hexamethylene diisocyanate (HDI), a large degree of unexplained intra- and inter-individual variability exists between estimated HDI exposure and urine HDA levels. We investigated the effect of individual and workplace factors on urine HDA levels using quantitative dermal and inhalation exposure data derived from a survey of automotive spray painters exposed to HDI. Painters' dermal and breathing-zone HDI-exposures were monitored over an entire workday for up to three separate workdays, spaced approximately one month apart. One urine sample was collected before the start of work with HDI-containing paints, and multiple samples were collected throughout the workday. Using mixed effects multiple linear regression modeling, coverall use resulted in significantly lower HDA levels (p = 0.12), and weekday contributed to significant variability in HDA levels (p = 0.056). We also investigated differences in urine HDA levels stratified by dichotomous and classification covariates using analysis of variance. Use of coveralls (p = 0.05), respirator type worn (p = 0.06), smoker status (p = 0.12), paint-booth type (p = 0.02), and more than one painter at the shop (p = 0.10) were all found to significantly affect urine HDA levels adjusted for creatinine concentration. Coverall use remained significant (p = 0.10), even after adjusting for respirator type. These results indicate that the variation in urine HDA level is mainly due to workplace factors and that appropriate dermal and inhalation protection is required to prevent HDI exposure.

Development of a sampling patch to measure dermal exposures to monomeric and polymeric 1,6-hexamethylene diisocyanate: a pilot study.

The purpose of this study was to develop and evaluate a patch sampler to monitor dermal exposures to monomeric and polymeric 1,6-hexamethylene diisocyanate (HDI) in the automotive refinishing industry. Different patch materials were used to construct the patches, and patches impregnated with a derivatizing solution were compared with those that were not impregnated. We observed that impregnated felt patches measured significantly more HDI monomer (p = 0.04) than non-impregnated patches in a controlled experiment. Both impregnated and non-impregnated patches were compared with the tape-strip method by monitoring three spray painters' dermal exposure to monomeric and polymeric HDI. Isocyanurate was the predominant species measured by all three sampler types with detectable levels in >86% of samples. Overall, tape-strips of exposed skin measured lower levels of monomeric and polymeric HDI than impregnated patch samplers at the same sampling site on the skin. Unlike tape-strips, impregnated patches are not as prone to evaporative or reactive losses or losses due to rapid penetration into the skin. Further investigations are warranted to evaluate these and other methods to measure dermal exposure to workers under occupational conditions to better understand the relationship between dermal exposure and internal dose.