Prevalence of skin sensitization and dermatitis among epoxy-exposed workers in the wind turbine industry.

BACKGROUND: A high prevalence of skin sensitization and dermatitis has been reported among workers exposed to epoxy components. OBJECTIVES: To estimate the risk of skin sensitization and dermatitis among workers exposed to epoxy components during production of wind turbine blades while using comprehensive safety measures. METHODS: A cross-sectional study of 180 highly epoxy-exposed production workers and 41 nonexposed office workers was conducted at two wind turbine blade factories in Denmark. Participants underwent a skin examination, were tested with a tailored patch test panel including epoxy-containing products used at the factories, and answered a questionnaire. RESULTS: Sixteen production workers (8·9%) were sensitized to an epoxy component compared with none of the office workers. Skin sensitization was more frequent within the first year of exposed employment. Strong selection bias by atopic status was indicated. Among nonatopic workers, the prevalence of dermatitis was higher among production workers (16·4%) than among office workers [6·5%, odds ratio (OR) 2·3, 95% confidence interval (CI) 0·6-9·1] and higher among the sensitized workers (43·8%) than the nonsensitized workers (14·6%, OR 4·5, 95% CI 1·6-12·7). Resins based on diglycidyl ether of bisphenol A and F were the most frequent sensitizers. One of the four workers sensitized to epoxy components used at the factories did not react to the epoxy resin of the TRUE test® panel. CONCLUSIONS: Despite comprehensive skin protection, sensitization and dermatitis are prevalent among highly epoxy-exposed workers in the wind turbine industry in Denmark. Our findings document the need for intensified preventive efforts and emphasize the importance of tailored patch testing. What is already known about this topic? Epoxy components are well-known sensitizers of the skin. A high prevalence of skin sensitization and dermatitis has been reported among workers exposed to epoxy components. Comprehensive protective equipment is recommended when working with epoxy components. What does this study add? Despite comprehensive skin protection, skin sensitization and dermatitis are prevalent among epoxy-exposed workers. We found that 40% of workers sensitized to epoxy products had dermatitis. Only 75% of the sensitized workers were detected by the epoxy resin of the TRUE test® , which emphasizes the importance of tailored testing.

Asthma-inducing potential of 28 substances in spray cleaning products-Assessed by quantitative structure activity relationship (QSAR) testing and literature review.

Exposure to spray cleaning products constitutes a potential risk for asthma induction. We set out to review whether substances in such products are potential inducers of asthma. We identified 101 spray cleaning products for professional use. Twenty-eight of their chemical substances were selected. We based the selection on (a) positive prediction for respiratory sensitisation in humans based on quantitative structure activity relationship (QSAR) in the Danish (Q)SAR Database, (b) positive QSAR prediction for severe skin irritation in rabbits and (c) knowledge on the substances' physico-chemical characteristics and toxicity. Combining the findings in the literature and QSAR predictions, we could group substances into four classes: (1) some indication in humans for asthma induction: chloramine, benzalkonium chloride; (2) some indication in animals for asthma induction: ethylenediaminetetraacetic acid (EDTA), citric acid; (3) equivocal data: hypochlorite; (4) few or lacking data: nitriloacetic acid, monoethanolamine, 2-(2-aminoethoxy)ethanol, 2-diethylaminoethanol, alkyldimethylamin oxide, 1-aminopropan-2-ol, methylisothiazolinone, benzisothiazolinone and chlormethylisothiazolinone; three specific sulphonates and sulfamic acid, salicylic acid and its analogue sodium benzoate, propane-1,2-diol, glycerol, propylidynetrimethanol, lactic acid, disodium malate, morpholine, bronopol and benzyl alcohol. In conclusion, we identified an asthma induction potential for some of the substances. In addition, we identified major knowledge gaps for most substances. Thus, more data are needed to feed into a strategy of safe-by-design, where substances with potential for induction of asthma are avoided in future (spray) cleaning products. Moreover, we suggest that QSAR predictions can serve to prioritise substances that need further testing in various areas of toxicology.

Measuring and predicting the emission rate of phthalate plasticizer from vinyl flooring in a specially-designed chamber.

The emission of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring (VF) was measured in specially designed stainless steel chambers. In duplicate chamber studies, the gas-phase concentration in the chamber increased slowly and reached a steady state level of 0.8-0.9 µg/m(3) after about 20 days. By increasing the area of vinyl flooring and decreasing that of the stainless steel surface within the chamber, the time to reach steady state was significantly reduced, compared to a previous study (1 month versus 5 months). The adsorption isotherm of DEHP on the stainless steel chamber surfaces was explicitly measured using solvent extraction and thermal desorption. The strong partitioning of DEHP onto the stainless steel surface was found to follow a simple linear relationship. Thermal desorption resulted in higher recovery than solvent extraction. Investigation of sorption kinetics showed that it takes several weeks for the sorption of DEHP onto the stainless steel surface to reach equilibrium. The content of DEHP in VF was measured at about 15% (w/w) using pressurized liquid extraction. The independently measured or calculated parameters were used to validate an SVOC emission model, with excellent agreement between model prediction and the observed gas-phase DEHP chamber concentrations.

Chemicals inhaled from spray cleaning and disinfection products and their respiratory effects. A comprehensive review.

Spray cleaning and disinfection products have been associated with adverse respiratory effects in professional cleaners and among residents doing domestic cleaning. This review combines information about use of spray products from epidemiological and clinical studies, in vivo and in vitro toxicological studies of cleaning chemicals, as well as human and field exposure studies. The most frequent chemicals in spray cleaning and disinfection products were compiled, based on registrations in the Danish Product Registry. The chemicals were divided into acids, bases, disinfectants, fragrances, organic solvents, propellants, and tensides. In addition, an assessment of selected cleaning and disinfectant chemicals in spray products was carried out. Chemicals of concern regarding respiratory effects (e.g. asthma) are corrosive chemicals such as strong acids and bases (including ammonia and hypochlorite) and quaternary ammonium compounds (QACs). However, the evidence for respiratory effects after inhalation of QACs is ambiguous. Common fragrances are generally not considered to be of concern following inhalation. Solvents including glycols and glycol ethers as well as propellants are generally weak airway irritants and not expected to induce sensitization in the airways. Mixing of certain cleaning products can produce corrosive airborne chemicals. We discuss different hypotheses for the mechanisms behind the development of respiratory effects of inhalation of chemicals in cleaning agents. An integrative assessment is needed to understand how these chemicals can cause the various respiratory effects.

Acute airway effects of ozone-initiated d-limonene chemistry: importance of gaseous products.

There are concerns about ozone-initiated chemistry, because the formation of gaseous oxidation products and ultrafine particles may increase complaints, morbidity and mortality. Here we address the question whether the gaseous products or the ultrafine particles from the ozone-initiated chemistry of limonene, a common and abundant indoor pollutant, cause acute airway effects. The effects on the airways by d-limonene, a ca. 16s old ozone/d-limonene mixture, and clean air were evaluated by a mice bioassay, from which sensory irritation of the upper airways, airflow limitation, and pulmonary irritation can be obtained. A denuder was inserted to separate the ultrafine particles from the gaseous products prior to the exposure chamber. Reduction of mean respiratory frequency (>30%) and 230% increase of time of brake were observed without denuder, during 30min exposure, to the ozonolyzed d-limonene mixture, which are indicative of prominent sensory effects. The initial concentrations (ppm) were 40 d-limonene and 4 ozone. The exposure concentrations (ppm) were about 35 d-limonene and 0.05 ozone. Formaldehyde and residual d-limonene, the salient sensory irritants, accounted for up to three-fourth of the sensory irritation. The upper airway effects reversed to baseline upon cessation of exposure. An effect on the conducting airways was also significant, which did not reverse completely upon cessation. Airway effects were absent with the denuder inserted, which did not alter the size distribution of ultrafine particles ( approximately 10mg/m(3)), significantly. The result was statistically indistinguishable from clean dry air. It is concluded that ultrafine particles that are generated from ozone-initiated d-limonene chemistry and denuded are not causative of sensory effects in the airways.

Secondary ozonides of substituted cyclohexenes: a new class of pollutants characterized by collision-induced dissociation mass spectrometry using negative chemical ionization.

Recent studies indicate that secondary ozonides of cyclic alkenes are formed in atmospheric reactions and may be relatively stable. The secondary ozonides (SOZs) of cyclohexene (1), 1-methylcyclohexene (2), 4-isopropyl-1-methylcyclohexene (3) and 4-isopropenyl-1-methylcyclohexene (limonene) (4) have been characterized by rapid gas chromatography electron ionization (EI), negative and positive chemical ionization (CI: ammonia, isobutane and methane) and collision-induced dissociation (CID) mass spectrometry. Both EI and positive CI spectra were found unsuitable for reproducible analysis. However, negative CI showed stable (M-H)(-) ions with minor fragmentation. CID of the (M-H)(-) ions resulted in simple and reproducible fragmentation patterns for all four SOZs with loss of m/z 18, 44 and 60, tentatively assigned as H(2)O, CO(2) and C(2)H(4)O(2) or CO(3), respectively. Thus, negative CI-MS-MS in combination with rapid gas chromatography is the preferred method for identification of secondary ozonides of cyclohexenes.

Upper airway irritation of terpene/ozone oxidation products (TOPS). Dependence on reaction time, relative humidity and initial ozone concentration.

Recently, we reported the formation of unidentified strong upper airway irritants in reaction mixtures of terpenes and ozone. The identified products included aldehydes, ketones and carboxylic acids. Here we report the effects of variation of reaction time, relative humidity and initial ozone concentration on irritant formation in a flow reaction system using R-(+)-limonene and isoprene. Upper airway irritation was measured in mice as reduction of the respiratory rate. For both substances maximum irritation was observed for low humidity (<2% RH)/short time (16-30 s) reaction mixtures, and both moderate humidity ( approximately 32% RH) and longer reaction times (60-90 s) resulted in significantly less irritation. These results suggest that some unidentified intermediates react with water vapor to give less irritating products. Irritation measured at four ozone concentrations (0.5, 1, 2 and 3.5 ppm) using low humidity/short time reaction conditions for limonene (50 ppm) and isoprene (500 ppm) revealed that at 0.5 ppm, irritation was at the same level as that for the pure terpenes, indicating that at 0.5 ppm ozone the combined irritant effect was near the no effect level for the product mixture.

Human reference values for acute airway effects of five common ozone-initiated terpene reaction products in indoor air.

Ozone-initiated monoterpene reaction products have been hypothesized to cause eye and airway complaints in office environments and some have been proposed to cause skin irritation and sensitization. The respiratory effects of 60 min exposures to five common oxidation products from abundant terpenoids (e.g. limonene), used as solvent and fragrance in common household products or present in skin lipids (e.g. squalene), were studied in a head out mouse bioassay. This allowed determination of acute upper airway (sensory) irritation, airflow limitation in the conducting airways, and pulmonary irritation in the alveolar region. Derived human reference values (RFs) for sensory irritation were 1.3, 0.16 and 0.3 ppm, respectively, for 4-acetyl-1-methylcyclohexene ( 0.2 ppm) [corrected], 3-isopropenyl-6-oxo-heptanal (IPOH), and 6-methyl-5-heptene-2-one (6-MHO). Derived RFs for airflow limitation were 0.8, 0.45, 0.03, and 0.5 ppm, respectively, for dihydrocarvone (DHC), 0.2 ppm [corrected], 4-oxo-pentanal (0.3 ppm) [corrected], and 6-MHO. Pulmonary irritation was unobserved as a critical effect. The RFs indicate that the oxidation products would not contribute substantially to sensory irritation in eyes and upper airways in office environments. Reported concentrations in offices of 6-MHO and 0.3 ppm [corrected]would not result in airflow limitation. However, based upon the RFs for IPOH and 0.3 ppm [corrected], precautionary actions should be considered that disfavor their formation in excess.

Predicting residential exposure to phthalate plasticizer emitted from vinyl flooring: a mechanistic analysis.

A two-room model is developed to estimate the emission rate of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring and the evolving gas-phase and adsorbed surface concentrations in a realistic indoor environment. Because the DEHP emission rate measured in a test chamber may be quite different from the emission rate from the same material in the indoor environment the model provides a convenient means to predict emissions and transport in a more realistic setting. Adsorption isotherms for phthalates and plasticizers on interior surfaces, such as carpet, wood, dust, and human skin, are derived from previous field and laboratory studies. Log-linear relationships between equilibrium parameters and chemical vapor pressure are obtained. The predicted indoor air DEHP concentration at steady state is 0.15 microg/m3. Room 1 reaches steady state within about one year, while the adjacent room reaches steady state about three months later. Ventilation rate has a strong influence on DEHP emission rate while total suspended particle concentration has a substantial impact on gas-phase concentration. Exposure to DEHP via inhalation, dermal absorption, and oral ingestion of dust is evaluated. The model clarifies the mechanisms that govern the release of DEHP from vinyl flooring and the subsequent interactions with interior surfaces, airborne particles, dust, and human skin. Although further model development, parameter identification, and model validation are needed, our preliminary model provides a mechanistic framework that elucidates exposure pathways for phthalate plasticizers, and can most likely be adapted to predict emissions and transport of other semivolatile organic compounds, such as brominated flame retardants and biocides, in a residential environment.

Release of VOCs and particles during use of nanofilm spray products.

Here, we present emission data on VOCs and particles emitted during simulated use of four commercial nanofilm spray products (NFPs) used for making easy-to-clean or self-cleaning surfaces on floors, ceramic tiles, and windows. The aim was to characterize the emitted VOCs and to provide specific source strength data for VOCs and particles released to the airduring use of the products. Containers with NFP were mounted on a spray-stand inside a closed stainless steel chamber with no air exchange. NFPs were sprayed in amounts corresponding to 1 m2 surface toward a target plate at a distance of 35 cm. Released VOCs were measured by a combination of air sampling on Tenax TA adsorbent followed by thermal desorption GC/MS and GC/FID analysis and real time measurements using a miniature membrane inlet mass spectrometer. Particles were measured using a fast mobility particle sizer and an aerosol particle sizer. A number of VOCs were identified, including small alcohols, ketones and ethers, chlorinated acetones, a perfluorinated silane, limonene, and cyclic siloxanes. The number of generated particles was on the order of 3 x 10(8) to 2 x 10(10) particles/m3 per g sprayed NFP and were dominated by nanosize particles.

Degradation of the adsorbent Tenax TA by nitrogen oxides, ozone, hydrogen peroxide, OH radical, and limonene oxidation products.

The degradation of the adsorbent Tenax TA was studied qualitatively by sampling oxidants common in indoor air followed by thermal desorption and gas chromatography. A total of 25 degradation products were identified. Several degradation products not reported previously were identified: 9 for nitrogen dioxide; 11 for ozone; 2 for hydrogen peroxide; 12 for hydroxyl radical; 1 for ozone-limonene mixtures, but none for nitrogen oxide. Whereas ozone shows a complex degradation of the adsorbent, hydrogen peroxide and limonene--ozone mixtures show few products. Nitrogen dioxide and the hydroxyl radical behave almost identically and produce 2,6-diphenyl-p-benzoquinone as the major degradation product. Reactant specific degradation products were identified for ozone (11) and nitrogen dioxide (1).

Upper airway and pulmonary effects of oxidation products of (+)-alpha-pinene, d-limonene, and isoprene in BALB/c mice.

The oxidation products (OPs) of ozone and the unsaturated hydrocarbons d-limonene, (+)-alpha-pinene, and isoprene have previously been shown to cause upper airway irritation in mice during 30-min acute exposures. This study evaluated the effects of OPs and the hydrocarbons themselves on the upper airways, the conducting airways, and the lungs over a longer exposure period. The time course of development of effects and the reversibility of effects were investigated; in addition, we assessed possible exacerbation of sensory responses of the airways to the unreacted hydrocarbons. Respiratory parameters in male BALB/c mice were monitored via head-out plethysmography. Exposures to OPs or hydrocarbons were for 60 min, followed by a 30-min challenge period with air or hydrocarbon, and a 15-min recovery period with air only. Experiments were also performed where limonene/ozone exposures were separated 6 h from the challenge period. Ozone concentration in the reaction mixture was 3.4 ppm, and concentrations of hydrocarbons were 47 ppm (alpha-pinene), 51 ppm (d-limonene), and 465 ppm (isoprene). Due to reaction, the ozone concentration at the point of exposure was less than 0.35 ppm; exposure to 0.30 ppm ozone for 60 min did not produce effects different from air-exposed control animals. As previously established, upper airway irritation was a prominent effect of OP exposure. In addition, over the longer exposure period we observed the development of airflow limitation that persisted for at least 45 min postexposure. All effects from limonene/ozone exposures were reversible within 6 h. Exposures to OPs did not cause enhanced upper airway irritation during challenge with the hydrocarbons, indicating that a 1-h exposure to OPs did not increase the sensitivity of the upper respiratory system. However, airflow limitation was exacerbated in animals exposed to d-limonene alone immediately following exposure to limonene OPs. These findings suggest that terpene/ozone reaction products may have moderate-lasting adverse effects on both the upper airways and pulmonary regions. This may be important in the context of the etiology or exacerbation of lower airway symptoms in office workers, or of occupational asthma in workers involved in industrial cleaning operations.