Skin exposure to epoxy chemicals in construction coating, assessed by observation, interviews, and measurements.

BACKGROUND: Epoxy resin systems (ERSs) are among the leading causes of occupational allergic contact dermatitis. OBJECTIVES: To identify riskful exposures and sources of skin exposure, and to quantify skin exposure to diglycidyl ether of bisphenol A (DGEBA) epoxy monomer, in construction coating work. METHODS: Skin exposure to epoxy chemicals was studied in 5 coating companies through (a) interviews and visual observation, (b) quantifying DGEBA on 12 workers' skin by tape-stripping, (c) measuring DGEBA on 23 surfaces by wipe-sampling, and (d) quantifying DGEBA in new sewage pipe. Acetone extracts of the tapes, wipes and sawdust from a newly hardened sewage pipe were analysed by gas chromatography/mass spectrometry. RESULTS: Identified riskful exposures were, for example, mixing ERSs, handling coating pots, and working above shoulder level. Epoxy stains on, for example, tools, equipment and clothing were seen in all workplaces. Protective gloves were of varying quality, and were not always suitable for chemicals. The amount of DGEBA on the workers' skin varied considerably. All screened tool handles were contaminated. Two-day-old epoxy sewage pipe contained 3.2% DGEBA. CONCLUSIONS: Construction coating entails skin contact with ERSs directly and via contaminated surfaces, personal protective equipment, and recently hardened epoxy materials. Observation is a useful method for assessing skin exposure in coating work.

Testing Penetration of Epoxy Resin and Diamine Hardeners through Protective Glove and Clothing Materials.

Efficient, comfortable, yet affordable personal protective equipment (PPE) is needed to decrease the high incidence of allergic contact dermatitis arising from epoxy resin systems (ERSs) in industrial countries. The aim of this study was to find affordable, user-friendly glove and clothing materials that provide adequate skin protection against splashes and during the short contact with ERS that often occurs before full cure. We studied the penetration of epoxy resin and diamine hardeners through 12 glove or clothing materials using a newly developed test method. The tests were carried out with two ERS test mixtures that had a high content of epoxy resin and frequently used diamine hardeners of different molar masses. A drop (50 µl) of test mixture was placed on the outer surface of the glove/clothing material, which had a piece of Fixomull tape or Harmony protection sheet attached to the inner surface as the collection medium. The test times were 10 and 30 min. The collecting material was removed after the test was finished and immersed into acetone. The amounts of diglycidyl ether of bisphenol A (DGEBA), isophorone diamine (IPDA), and m-xylylenediamine (XDA) in the acetone solution were determined by gas chromatography with mass spectrometric detection. The limit for acceptable penetration of XDA, IPDA, and DGEBA through glove materials was set at 2 µg cm(-2). Penetration through the glove materials was 1.4 µg cm(-2) or less. The three tested chemical protective gloves showed no detectable penetration (<0.5 µg cm(-2)). Several affordable glove and clothing materials were found to provide adequate protection during short contact with ERS, in the form of, for example, disposable gloves or clothing materials suitable for aprons and as additional protective layers on the most exposed parts of clothing, such as the front of the legs and thighs and under the forearms. Every ERS combination in use should be tested separately to find the best skin protection material, and this can be done by using this simple test method.

Occupational contact dermatitis caused by aniline epoxy resins in the aircraft industry.

BACKGROUND: Tetraglycidyl-4,4'-methylenedianiline (TGMDA) is an aniline epoxy resin used in, for example, resin systems of pre-impregnated composite materials (prepregs) of the aircraft industry. Allergic contact dermatitis caused by TGMDA in prepregs has been described previously. OBJECTIVES: To report on 9 patients with occupational allergic contact dermatitis caused by TGMDA in epoxy glues used in helicopter assembly. METHODS: The patients were examined with patch testing at the Finnish Institute of Occupational Health in 2004-2009. The first patient was diagnosed by testing both components of two epoxy glues from the workplace, and was also tested with glue ingredients, including TGMDA. The following patients were tested with the glues and TGMDA. The resin parts of the glues were analysed for their epoxy compounds, including TGMDA. RESULTS: All of the patients had a patch test reaction to one or both of the resin parts of the TGMDA-containing glues. Eight of them had a strong allergic reaction to TGMDA, and one had a doubtful reaction to TGMDA. Two of the patients also had an allergic reaction to triglycidyl-p-aminophenol (TGPAP), another aniline epoxy resin, which was not present in the TGMDA-containing glues. CONCLUSIONS: In aircraft industry workers with suspected occupational dermatitis, aniline epoxy resins should be considered and patch tested as possible contact allergens.

Contact allergy to reactive diluents and related aliphatic epoxy resins.

BACKGROUND: Diglycidyl ether of bisphenol A resin (DGEBA-R) is the most common sensitizer in epoxy systems, but a minority of patients also develop contact allergy to reactive diluents. OBJECTIVES: To analyse the frequency and clinical relevance of allergic reactions to different epoxy reactive diluents and related aliphatic epoxy resins. METHODS: Test files (January 1991 to June 2014) were screened, and the clinical records of patients with allergic reactions were analysed for occupation, concomitant allergic reactions, and exposure. RESULTS: A total of 67 patients reacted to at least one of the compounds. The largest numbers of allergic reactions were to phenyl glycidyl ether (PGE; n = 41), 1,4-butanediol diglycidyl ether (BDDGE; n = 34), and p-tert-butylphenyl glycidyl ether (PTBPGE; n = 19). Ten of the patients did not have contact allergy to DGEBA-R. The reactions of 5 of these were related to the use of BDDGE-containing products. We found no significant exposure to PGE or PTBPGE in patients sensitized to them, but some of the patients had used cresyl glycidyl ether-containing products. CONCLUSIONS: Allergic reactions to reactive diluents and related aliphatic epoxy resins usually occurred together with reactions to DGEBA-R. BDDGE was the clinically most significant compound, and was the sole cause of occupational allergic contact dermatitis in 3 patients.

A new penetration test method: protection efficiency of glove and clothing materials against diphenylmethane diisocyanate (MDI).

Reported cases of allergic contact dermatitis caused by methylenediphenyl diisocyanate (MDI) have increased and thereby increased the need for adequate skin protection. Current standardized permeation and penetration test methods give information about efficacy of protective materials against individual components of the polyurethane systems. They do not give information of what kind of clothing materials workers should wear against splashes when handling mixed MDI-polyurethane formulations, which contain MDI, its oligomers, and polyols. The aim of this study was to develop and validate a sensitive penetration test method that can be used to select clothing that is protective enough against uncured splashes of MDI-polyurethane, still easy to use, and also, to find affordable glove materials that provide adequate protection during a short contact. The penetration of MDI through eight representative glove or clothing materials was studied with the developed test procedure. One MDI hardener and two polymeric MDI (PMDI)-polyol formulations representing different curing times were used as test substances. The materials tested included work clothing (woven) fabric, arm shields (nonwoven fabric), old T-shirt, winter gloves, and gloves of nitrile rubber, leather, vinyl (PVC), and natural rubber. A drop (50 µl) of test substance was added to the outer surface of the glove/clothing material, which had Tape Fixomull attached to the inner surface as a collection medium. After penetration times of 5 or 20min, the collecting material was removed and immediately immersed into acetonitrile containing 1-(2-methoxyphenyl)-piperazine for derivatization. The formed urea derivatives of 2,4'-MDI and 4,4'-MDI were analysed using liquid chromatography with mass spectrometric and UV detection. The precision of the test method was good for the material with high penetration (work clothing fabric) of MDI, as the relative standard deviation (RSD) was 14 and 20%. For the arm shield with a low penetration (the nonwoven fabric), the precision was lower with RSDs of 35 and 50%. For two clothing materials, the penetration was high (134-577 µg cm(-2)). Low penetration (<0.5 µg cm(-2)) was shown by the arm shield and the natural rubber glove. Three glove materials showed no detectable MDI penetration (<0.002 µg cm(-2)). Two affordable glove materials (natural rubber and nitrile rubber) and one clothing material (dust proof arm shield) that can provide adequate protection during short contact with solvent free PMDI formulations were found. The new test procedure should be standardized in order to get a new international penetration standard.

Role of dermal exposure in systemic intake of methylenediphenyl diisocyanate (MDI) among construction and boat building workers.

The causal relationship between inhalation exposure to methylenediphenyl diisocyanate (MDI) and the risk of occupational asthma is well known, but the role of dermal exposure and dermal uptake of MDI in this process is still unclear. The aims of this study were to measure dermal exposure to and the dermal uptake of MDI among workers (n=24) who regularly handle MDI-urethanes. Dermal exposure was measured by the tape-strip technique from four sites on the dominant hand and arm. The workers with the highest exposure (n=5) were biomonitored immediately after their work shift, in the evening and the next morning, using urinary 4,4´methylenedianiline (MDA) as a marker. Dermal uptake was evaluated by comparing workers' MDA excretions both when they were equipped with respiratory protective devices (RPDs) and when they did not use them. The measured amounts of MDI on their hands varied from below 0.1 to 17 µg/10 cm(2) during the test. MDI concentrations were in the range of 0.08 to 27 µg m(-3) in the breathing zone outside the RPDs. MDA concentrations varied from 0.1 to 0.2 µmol mol(-1) creatinine during the test period. The decreasing effect of RPDs on inhalation exposure was absent in the next morning urine samples; this excretion pattern might be an indication of dermal uptake of MDI.

Occupational contact dermatitis caused by D-limonene.

BACKGROUND: Limonene is widely used as a fragrance substance and solvent in cleansing products. Oxidized limonene is a frequent contact allergen among consumers of cosmetics, personal care products, and scented household cleaning products. Less is known about the sources of occupational exposure and occupational contact dermatitis caused by limonene. OBJECTIVE: To report 14 patients with occupational contact allergy to limonene. METHODS: The patients were examined in 2008-2013. An in-house preparation of oxidized limonene was patch tested as 3% and 5% in petrolatum from 2008 to August 2010, and after this as 3%, 1% and 0.3% pet. From 2012 onwards, a commercial test substance of limonene hydroperoxides was also used. We assessed the patients' occupational and domestic exposure to limonene. RESULTS: Occupational limonene allergy was observed in workers who used limonene-containing machine-cleaning detergents and hand cleansers, and in workers who used limonene-containing surface cleaners and dishwashing liquids similar to those used by consumers. In 3 cases, the occupational limonene allergy resulted from work-related use of limonene-containing, leave-on cosmetic products. CONCLUSIONS: Limonene is a frequent occupational sensitizer in hand cleansers and cleaning products. Occupational limonene contact allergy may also be caused by exposure to cosmetic products scented with limonene.

Contact allergy to epoxy hardeners.

BACKGROUND: Diglycidylether of bisphenol A resin is the most important sensitizer in epoxy systems, but a minority of patients develop concomitant or solitary contact allergy to epoxy hardeners. At the Finnish Institute of Occupational Health, several in-house test substances of epoxy hardeners have been tested in a special epoxy compound patch test series. OBJECTIVES: To analyse the frequency and clinical relevance of allergic reactions to different epoxy hardeners. METHODS: Test files (January 1991 to March 2013) were screened for contact allergy to different epoxy hardeners, and the clinical records of patients with allergic reactions were analysed for occupation, concomitant allergic reactions, and exposure. RESULTS: The most commonly positive epoxy hardeners were m-xylylenediamine (n = 24), 2,4,6-tris-(dimethylaminomethyl)phenol (tris-DMP; n = 14), isophorone-diamine (n = 12), and diethylenetriamine (n = 9). Trimethylhexamethylenediamine (n = 7), tetraethylenepentamine (n = 4), and triethylenetetramine (n = 2) elicited some reactions, although most patients were found to have no specific exposure. Allergic reactions to hexamethylenetetramine, dimethylaminopropylamine and ethylenediamine dihydrochloride were not related to epoxy products. CONCLUSIONS: Tris-DMP is an important sensitizer in epoxy hardeners, and should be included in the patch test series of epoxy chemicals.

Permeation tests of glove and clothing materials against sensitizing chemicals using diphenylmethane diisocyanate as an example.

Diphenylmethane diisocyanate (MDI) is a sensitizing chemical that can cause allergic contact dermatitis and asthma. Protective gloves and clothing are necessary to prevent skin exposure. Breakthrough times are used for the selection of chemical protective gloves and clothing. In the EN 374-3:2003 European standard, breakthrough time is defined as the time in which the permeation reaches the rate of 1.0 µg min(-1) cm(-2) through the material. Such breakthrough times do not necessarily represent safe limits for sensitizing chemicals. We studied the permeation of 4,4'-MDI through eight glove materials and one clothing material. The test method was derived from the EN 374-3 and ASTM F 739 standards. All measured permeation rates were below 0.1 µg min(-1) cm(-2), and thus, the breakthrough times for all the tested materials were over 480min, when the definitions of EN 374-3 and ASTM F 739 for the breakthrough time were used. Based on the sensitizing capacity of MDI, we concluded that a cumulative permeation of 1.0 µg cm(-2) should be used as the end point of the breakthrough time determination for materials used for protection against direct contact with MDI. Using this criterion for the breakthrough time, seven tested materials were permeated in <480min (range: 23-406min). Affordable chemical protective glove materials that had a breakthrough time of over 75min were natural rubber, thick polyvinylchloride, neoprene-natural rubber, and thin and thick nitrile rubber. We suggest that the current definitions of breakthrough times in the standard requirements for protective materials should be critically evaluated as regards MDI and other sensitizing chemicals, or chemicals highly toxic via the skin.

Screening occupational contact allergy to bisphenol F epoxy resin.

BACKGROUND: Epoxy resins based on diglycidyl ether of bisphenol F (DGEBF) are widely used as such in applications requiring chemical resistance, and also together with diglycidyl ether of bisphenol A resin (DGEBA-R). Concomitant patch test reactions to DGEBA-R and DGEBF resin (DGEBF-R) are common. Previous studies have yielded conflicting results on the frequency of independent DGEBF-R contact allergies. OBJECTIVES: To report the results of over 11 years of screening with DGEBF-R. METHODS: An in-house test substance of DGEBF-R (Epikote 862) was tested in the baseline patch test series, first at 1% and later at 0.25%. Test files were screened for allergic reactions to DGEBF-R and DGEBA-R, and the clinical records of positively reacting patients were analysed for occupation and exposure. RESULTS: Among 1972 patients, 66 (3.3%) reacted to DGEBF-R and 96 (4.9%) to DGEBA-R. Independent DGEBF-R allergies were seen in 5 patients only, and independent DGEBA-R allergies in 35. Specific exposure to DGEBF-R was found in 26 patients. The main occupational fields were the aircraft industry, the electrical and sports equipment industry, boat building, painting/floor coating, tile setting, and pipe relining. CONCLUSIONS: Independent contact allergies to DGEBF-R were rare, and screening with it was not found to be useful.

Triphenyl phosphite, a new allergen in polyvinylchloride gloves.

BACKGROUND: Contact allergy to polyvinylchloride (PVC) gloves has been reported relatively seldom. In spring 2011, 5 of our patients had patch test reactions to PVC gloves. We obtained a collection of PVC raw materials from industrial producers and suppliers of chemical compounds to be patch tested on patients with suspected PVC glove contact allergy. OBJECTIVES: To report the first results of these new test substances. METHODS: The patients were patch tested with the newly obtained test substances, plastics and glues series, and isocyanates and isocyanate prepolymers. We analysed nine PVC glove samples for triphenyl phosphate and its derivatives. RESULTS: Two patients reacted to a technical PVC antioxidant and one of its components, triphenyl phosphite (TPP). Contact allergy to TPP was very strong in 1 patient, and was the main cause of her hand dermatitis, whereas the other patient also had other contact allergies explaining her symptoms. Three patients reacted to their PVC gloves, but the specific allergen was not identified. Six PVC glove samples contained TPP at concentrations of 0.004-0.099%. TPP transforms into triphenyl phosphate during storage. CONCLUSIONS: TPP represents a new allergen in PVC gloves. It was detected in several PVC gloves in fairly high concentrations.

Occupational contact allergy to monomeric isocyanates.

BACKGROUND: The monomeric isocyanates diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate (TDI), isophorone diisocyanate (IPDI) and 1,6-hexamethylene diisocyanate (HDI) are used in polyurethane products and sometimes cause contact allergy. OBJECTIVES: To describe patients with isocyanate contact allergy in an occupational dermatology clinic. METHODS: Test files were screened for allergic reactions to isocyanates and 4,4'-diaminodiphenylmethane (MDA). Patients with allergic reactions to some of the allergens were analysed for occupation, exposure, concomitant reactions to other allergens, and diagnosis. RESULTS: Over a period of almost 13 years, 54 patients reacted to isocyanates (9 to IPDI, 12 to MDI, 6 to TDI, and 1 to HDI) or MDA (44 patients). The motor vehicle, electronics and paint industries, and painting and construction work, were among the most significant occupational fields. An in-house polymeric MDI (PMDI) test substance was superior to commercial MDI preparations. About half of the occupational cases related to MDI products were diagnosed by testing MDA. The most prominent cause of IPDI allergy comprised polyurethane paint hardeners. Some of the IPDI reactions could be explained by cross-allergy to isophoronediamine in epoxy products. Specific exposure to MDA was difficult to trace. CONCLUSIONS: MDA and PMDI test substances were significant in the diagnosis of MDI contact allergy.

Occupational asthma related to low levels of airborne methylene diphenyl diisocyanate (MDI) in orthopedic casting work.

Orthopedic plaster casts contain methylene diphenyl diisocyanate (MDI). A few case reports have suggested occupational asthma to MDI in casting work. However, the knowledge of the exposure levels related to the occupational asthma cases is lacking. We report on two occupational asthma cases due to MDI in nurses irregularly applying orthopedic plaster casts, verified with placebo controlled specific inhalation challenge. The levels of MDI in the air were measured in the exposure chamber during the specific inhalation challenges with a quantitative method including filter collection and subsequent liquid chromatography-mass spectrometry (LC-MS) analysis of the isocyanate groups. In order to estimate the level of airborne MDI in casting work, measurements were conducted also in two hospitals during the application and removal of synthetic plaster casts using the same method. The concentrations were well below the occupational exposure limit in both specific inhalation challenge and hospital measurements. Based on our findings, even minor exposure to airborne MDI in casting work can cause an asthmatic reaction in some patients.

Occupational methacrylate and acrylate allergy--cross-reactions and possible screening allergens.

BACKGROUND: Acrylic resin monomers, especially acrylates and methacrylates, are important occupational allergens. AIMS: To analyse patterns of concomitant patch test reactions to acrylic monomers in relation to exposure, and to suggest possible screening allergens. PATIENTS/METHODS: We reviewed the patch test files for the years 1994-2009 at the Finnish Institute of Occupational Health for allergic reactions to acrylic monomers, and analysed the clinical records of sensitized patients. RESULTS: In a group of 66 patients allergic to an acrylic monomer, the most commonly positive allergens were three methacrylates, namely ethyleneglycol dimethacrylate (EGDMA), 2-hydroxyethyl methacrylate (2-HEMA) and 2-hydroxypropyl methacrylate (2-HPMA), and an acrylate, namely diethyleneglycol diacrylate (DEGDA). The patterns of concomitant reactions imply that exposure to methacrylates may induce cross-reactivity to acrylates, whereas exposure to acrylates usually does not lead to cross-allergy to methacrylates. Screening for triethyleneglycol diacrylate (TREGDA) in the baseline series was found to be useful, as 3 of 8 patients with diagnosed occupational acrylate allergy might have been missed without the screening. CONCLUSIONS: A short screening series of four allergens, EGDMA, DEGDA, 2-HPMA and pentaerythritol triacrylate (PETA), would have screened 93% of our 66 patients; each of the remaining 5 patients reacted to different acrylic monomer(s).

Contact allergy to epoxy (meth)acrylates.

BACKGROUND: Contact allergy to epoxy (meth)acrylates, 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (bis-GMA), 2,2-bis[4-(2-hydroxy-3-acryloxypropoxy)phenyl]-propane (bis-GA), 2,2-bis[4-(methacryl-oxyethoxy)phenyl] propane (bis-EMA), 2,2-bis[4-(methacryloxy)phenyl]-propane (bis-MA), and glycidyl methacrylate (GMA) is often manifested together with contact allergy to diglycidyl ether of bisphenol A (DGEBA) epoxy resin. OBJECTIVE: To analyse patterns of concomitant allergic reactions to the five epoxy (meth)acrylates in relation to exposure. METHODS: We reviewed the 1994-2008 patch test files at the Finnish Institute of Occupational Health (FIOH) for reactions to the five epoxy (meth)acrylates, and examined the patients' medical records for exposure. RESULTS: Twenty-four patients had an allergic reaction to at least one of the studied epoxy (meth)acrylates, but specific exposure was found only in five patients: two bis-GMA allergies from dental products, two bis-GA allergies from UV-curable printing inks, and one bis-GA allergy from an anaerobic glue. Only 25% of the patients were negative to DGEBA epoxy resin. CONCLUSIONS: The great majority of allergic patch test reactions to bis-GMA, bis-GA, GMA and bis-EMA were not associated with specific exposure, and cross-allergy to DGEBA epoxy resin remained a probable explanation. However, independent reactions to bis-GA indicated specific exposure. Anaerobic sealants may induce sensitization not only to aliphatic (meth)acrylates but also to aromatic bis-GA.

[Occupational asthma in a structure nail maker]. / Rakennekynsien tekijän ammattiastma.

Chemicals that may cause allergy are being used in structure nails. In this case report two structure nail makers are described, who were diagnosed with occupational asthma in clinical studies. The studies included an inhalational exposure simulating the work. The causative agents of occupational asthma are apparently the acrylate compounds contained in the chemicals; use of these compounds has previously been linked with allergic contact dermatitis and asthma. Since the making of structure nails involves health risks, such work requires appropriate premises and personal protection.

Analysis of allergens in metalworking fluids.

BACKGROUND: Metalworking fluids (MWFs) are well-known causes of occupational contact dermatitis in machinists. OBJECTIVE: To gain information about skin sensitizers in MWFs and to compare it with the information in safety data sheets (SDSs). METHODS: A total of 17 samples of MWF concentrates were analysed for skin sensitizers known or suspected to be used in MWF. Alkanolamines, formaldehyde, isothiazolinones, methyldibromo glutaronitrile (MDBGN), and iodopropynyl butylcarbamate (IPBC) were separated by liquid chromatography. Resin acids of colophonium (colophony) were separated by gas chromatography. The substances were identified with mass spectrometric detection and ultraviolet detection. RESULTS: Of the MWFs, 15 contained 6-39% of alkanolamines, mostly monoethanolamine and triethanolamine. Formaldehyde was detected in all MWFs: the concentrations of total formaldehyde ranged between 0.002% and 1.3%. Benzisothiazolinone and octylisothiazolinone were detected in one fluid each. IPBC was detected in nine MWFs, and the highest concentration was 0.09%. Methylisothiazolinone and MDBGN were not detected in any of the fluids. Resin acids of colophonium were detected in seven MWFs in concentrations ranging from 0.41% to 3.8%. On the whole, the allergens analysed were poorly declared in the SDSs. CONCLUSIONS: The content of total formaldehyde was not declared in any SDS. IPBC, a relatively new allergen, seems to be common in MWFs. Isothiazolinones may be relevant allergens of machinists, and they should be analysed in MWFs in case other sources are not identified. The occupational relevance of positive patch test results to MWF ingredients in machinists is difficult to determine if information in the SDSs is relied upon.