Trends and Characteristics of Manufactured Cannabis Product and Cannabis Plant Product Exposures Reported to US Poison Control Centers, 2017-2019

This cross-sectional study examines reports of cannabis exposure at US poison control centers for trends in patient and product characteristics, stratified by manufactured cannabis products and plant materials.

Respiratory surveillance for coal mine dust and artificial stone exposed workers in Australia and New Zealand: A position statement from the Thoracic Society of Australia and New Zealand

Coal mine lung dust disease (CMDLD) and artificial stone (AS) silicosis are preventable diseases which have occurred in serious outbreaks in Australia recently. This has prompted a TSANZ review of Australia's approach to respiratory periodic health surveillance. While regulating respirable dust exposure remains the foundation of primary and secondary prevention, identification of workers with early disease assists with control of further exposure, and with the aims of preserving lung function and decreasing respiratory morbidity in those affected. Prompt detection of an abnormality also allows for ongoing respiratory specialist clinical management. This review outlines a medical framework for improvements in respiratory surveillance to detect CMDLD and AS silicosis in Australia. This includes appropriate referral, improved data collection and interpretation, enhanced surveillance, the establishment of a nationwide Occupational Lung Disease Registry and an independent advisory group. These measures are designed to improve health outcomes for workers in the coal mining, AS and other dust-exposed and mining industries.

Artificial stone-associated silicosis in China: A prospective comparison with natural stone-associated silicosis

BACKGROUND AND OBJECTIVE

We recently noted a dramatic increase in the number of patients with accelerated silicosis associated with exposure to artificial stone dust. Therefore, the natural history of artificial stone-associated silicosis was compared with that of natural stone-associated silicosis.

METHODS

A total of 18 patients with artificial stone-associated silicosis and 63 with natural stone-associated silicosis were diagnosed sequentially in 2018 and followed up for a period of 6-12 months. Data were collected from clinical charts.

RESULTS

The median duration of exposure prior to onset of symptoms of silicosis was shorter for patients who had been exposed to artificial stone dust (6.4 vs 29.3 years, P < 0.01). Four of the 18 patients experienced rapid deterioration in lung function over the follow-up period, with declines in pre-bronchodilator FVC of 587 (210-960) mL/year and FEV1 of 625 (360-860) mL/year. GGO, PMF, emphysema and pulmonary artery widening were more frequently observed on computed tomography scans of patients with artificial stone-associated silicosis than of those with natural stone-associated silicosis. Approximately 38.9% of the patients with artificial stone-associated silicosis were lung transplant candidates and 27.8% died, both rates being significantly higher than in patients with natural stone-associated silicosis (3.2% and 0%, both P < 0.01).

CONCLUSION

Compared to natural stone-associated silicosis, artificial stone-associated silicosis was characterized by short latency, rapid radiological progression, accelerated decline in lung function and high mortality.

Severe Silicosis in Engineered Stone Fabrication Workers - California, Colorado, Texas, and Washington, 2017-2019

Silicosis is an incurable occupational lung disease caused by inhaling particles of respirable crystalline silica. These particles trigger inflammation and fibrosis in the lungs, leading to progressive, irreversible, and potentially disabling disease. Silica exposure is also associated with increased risk for lung infection (notably, tuberculosis), lung cancer, emphysema, autoimmune diseases, and kidney disease (1). Because quartz, a type of crystalline silica, is commonly found in stone, workers who cut, polish, or grind stone materials can be exposed to silica dust. Recently, silicosis outbreaks have been reported in several countries among workers who cut and finish stone slabs for countertops, a process known as stone fabrication (2-5). Most worked with engineered stone, a manufactured, quartz-based composite material that can contain >90% crystalline silica (6). This report describes 18 cases of silicosis, including the first two fatalities reported in the United States, among workers in the stone fabrication industry in California, Colorado, Texas, and Washington. Several patients had severe progressive disease, and some had associated autoimmune diseases and latent tuberculosis infection. Cases were identified through independent investigations in each state and confirmed based on computed tomography (CT) scan of the chest or lung biopsy findings. Silica dust exposure reduction and effective regulatory enforcement, along with enhanced workplace medical and public health surveillance, are urgently needed to address the emerging public health threat of silicosis in the stone fabrication industry.

An assessment of formaldehyde emissions from laminate flooring manufactured in China

Formaldehyde emissions from two laminate flooring products, labeled as California Air Resources Board (CARB) compliant, were evaluated. Passive 24-hr samples (n = 79) and real-time measurements were collected following installation and removal of the products in two rooms of similar size. Mean formaldehyde concentrations following installation were 0.038 and 0.022 ppm for Products 1 and 2 respectively, and 7 days after flooring removal the concentrations returned to background pre-installation levels. Both products were also evaluated in a small chamber (ASTM D6007) using Deconstructive (de-laminated product) and Non-Deconstructive (intact product) methods. Deconstructive testing showed that Product 1 exceeded the applicable CARB emission standard by 4-fold, while Product 2 was equivalent to the standard. Non-Deconstructive measurements were far below the Deconstructive results and were used to predict 24-hr steady-state room air concentrations. Based on the products that we tested (one of which was found to not be compliant with the CARB standard), the airborne formaldehyde concentrations measured following installation in a real-world setting would not be expected to elicit adverse acute health effects.

Asbestos Products, Hazards, and Regulation

Asbestos is present in the United States in a multitude of products used in past decades, and in some products that continue to be imported and domestically produced. We have limited information on the hazards posed by some of these individual products and no information at all on most of them. Legal discovery of corporate documents has shed some light on the use of asbestos in some products and exposures from asbestos in others, sometimes adding considerably to what was in the published literature. But liability concerns have motivated corporate efforts to curtail governmental public health guidance on long-recognized hazards to workers. Liability considerations have also evidently led, in the case of asbestos brake linings, to the support of publication in the scientific literature of review articles denying in the 21st century what had been widely accepted and established in health policy in the 20th century. This report is an effort to illustrate the suppression and emergence of scientific knowledge in a climate of regulation and liability. Examples discussed are vinyl-asbestos flooring, feminine hygiene products, automotive friction materials, and asbestos contamination of other minerals such as talc and vermiculite. Global efforts to deal with the hazards of continuing marketing of asbestos products are also discussed.

A methodology using in-chair movements as an objective measure of discomfort for the purpose of statistically distinguishing between similar seat surfaces

This study presents a method for objectively measuring in-chair movement (ICM) that shows correlation with subjective ratings of comfort and discomfort. Employing a cross-over controlled, single blind design, healthy young subjects (n = 21) sat for 18 min on each of the following surfaces: contoured foam, straight foam and wood. Force sensitive resistors attached to the sitting interface measured the relative movements of the subjects during sitting. The purpose of this study was to determine whether ICM could statistically distinguish between each seat material, including two with subtle design differences. In addition, this study investigated methodological considerations, in particular appropriate threshold selection and sitting duration, when analysing objective movement data. ICM appears to be able to statistically distinguish between similar foam surfaces, as long as appropriate ICM thresholds and sufficient sitting durations are present. A relationship between greater ICM and increased discomfort, and lesser ICM and increased comfort was also found.

[Malignant mesotheliomas with unknown exposure to asbestos: a re-examination]

INTRODUCTION

Malignant Mesothelioma (MM) is a rare neoplasm associated with asbestos exposure. In 24,5% of MM cases reported to the Lombardy Mesothelioma Registry (LMR), asbestos exposure has been defined as "unknown".

OBJECTIVE

To evaluate the cases with "unknown exposure to asbestos" diagnosed in 2000-2004 in agreement with new knowledge about source of asbestos exposure.

METHODS

Information regarding exposure has been reviewed in order to select the cases susceptible of further investigations, including: interview of relatives and/or colleagues; further evaluations by local PSAL (Prevention and Security in workplace) services; contact of industrial hygienists; analysis of production processes. The same procedure has been followed for extra-occupational exposure. These cases have been subjected to the LMR evaluation group.

RESULTS

Fourthy four out of 364 (12,1%) MM have been reclassified. In 47,7% of the cases, a "possible occupational exposure" has been recognized, 15,9% have been attributed a "certain occupational exposure", while 36,4% an extra-occupational (domestic, environmental and leisure-time) exposure. No significant differences between age, sex, cancer site, diagnostic certainty, residence, year of diagnosis, interviewed subjects were detected. The occupational sector with the highest amount of reclassifications was the clothing production.

CONCLUSIONS

The detailed reconstruction of clinical and occupational history and of lifestyle habits of patients affected by MM, close cooperation with Local Services of Occupational Medicine and literature review make it possible for previously overlooked asbestos exposure to be acknowledged.

Liver damage in automotive and industrial workers of the glass

OBJECTIVE

High doses of organic solvents can cause hepatic disease. We investigated whether exposure to low doses of solvents in automotive and industrial workers may lead to changes in liver tests.

METHODS

We studied the liver parameters (glutamic oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), gamma-glutamyl-traspeptidasi (γ-GT), alkaline phosphatase (PHA), total (TB) and direct bilirubin (DB) of 24 workers exposed to organic solvents and of 30 unexposed controls.

RESULTS

A significant increase of GOT, GPT and γ-GT was found in exposed workers compared to unexposed controls workers. The ratio GPT/GOT was significantly higher among the exposed compared to controls.

CONCLUSIONS

The results confirmed the hypothesis that exposure to low doses of solvents may determine a liver damage.

Characterisation factors for life cycle impact assessment of sound emissions

Noise is a serious stressor affecting the health of millions of citizens. It has been suggested that disturbance by noise is responsible for a substantial part of the damage to human health. However, no recommended approach to address noise impacts was proposed by the handbook for life cycle assessment (LCA) of the European Commission, nor are characterisation factors (CFs) and appropriate inventory data available in commonly used databases. This contribution provides CFs to allow for the quantification of noise impacts on human health in the LCA framework. Noise propagation standards and international reports on acoustics and noise impacts were used to define the model parameters. Spatial data was used to calculate spatially-defined CFs in the form of 10-by-10-km maps. The results of this analysis were combined with data from the literature to select input data for representative archetypal situations of emission (e.g. urban day with a frequency of 63 Hz, rural night at 8000 Hz, etc.). A total of 32 spatial and 216 archetypal CFs were produced to evaluate noise impacts at a European level (i.e. EU27). The possibility of a user-defined characterisation factor was added to support the possibility of portraying the situation of full availability of information, as well as a highly-localised impact analysis. A Monte Carlo-based quantitative global sensitivity analysis method was applied to evaluate the importance of the input factors in determining the variance of the output. The factors produced are ready to be implemented in the available LCA databases and software. The spatial approach and archetypal approach may be combined and selected according to the amount of information available and the life cycle under study. The framework proposed and used for calculations is flexible enough to be expanded to account for impacts on target subjects other than humans and to continents other than Europe.

[Trend of the asbestos related diseases mortality in workers of a company in the province Cremona which manufactured asbestos products]

The study analyzes the trend of asbestos-related diseases and mortality in workers of a company in the province of Cremona which manufactured asbestos products. It is confirmed that the exposure to a high concentration of asbestos fibers (estimated to more than 20 fibers/cc) strictly correlates with the onset of pathologies from asbestos. In the studied population were found 19 cases of neoplastic diseases (12 mesotheliomas and 7 bronchopulmonary carcinomas). This figure, compared to the company working population, which over the years has been an average of 80 units, while not enabling to calculate an incidence rate due to the lack of reliable data on population, is indicative of a very significant cause-effect relationship since these are neoplastic diseases that can still arise. So it is necessary to continue the health monitoring of formerly exposed workers and appropriate to try to extend it to all workers of the asbestos compartment.

Asbestos-related diseases in entertainment workers

OBJECTIVES

To investigate asbestos exposure in 4 patients (3 cases of malignant mesothelioma and 1 case ofpleural plagues) previously employed in the entertainment business.

METHODS

The patients were seen at the Occupational Health Unit of the "Clinica del Lavoro Luigi Devoto" in Milan (Italy). Information regarding exposure to asbestos (occupational, environmental, and familial) was collected through a standardized questionnaire administered to the patients by an occupational physician.

RESULTS AND CONCLUSION

The presence of asbestos in the building structures and its use were described by all patients. The presence of asbestos in public buildings used for entertainment such as cinemas and theatres was in fact confirmed by the Occupational Health Services of the Local Heath Unit. An occupational aetiology was recognised in all the cases mentioned above, thus leading to the identification of an atypical occupational sector at risk in the past for asbestos exposure,

An integrated occupational health consultation model for the medical supply manufacturing industry

In this research, we designed a three-stage consultation procedure and eight major consultation items in order to construct an integrated occupational health consultation model that emphasizes both inspection and consultation. The main characteristics of the proposed model include cooperation among governmental departments, combining non-governmental professional consulting organizations, and establishing partnerships with industrial associations. This model has clear active and passive performance indicators and includes technical guidance during consultation as well as the exit mechanism after consultation. This consultation model enables small- and medium-sized enterprises to achieve environmental improvements with minimum investment. Companies that improved after consultation have a mean ethylene oxide exposure concentration, for the time weighted average, that dropped from 7.36 ± 16.88 ppm to 0.76 ± 1.35 ppm (p<0.01). In addition, the overall company compliant item ratio for regulations increased from 34.1% to 89.7%. The above results demonstrate the integrated occupational health consultation model assists small- and medium-sized enterprises in reducing exposure concentrations at operational sites. Our results further demonstrate the feasibility of successfully implementing the proposed consultation model within Taiwan's medical supply manufacturing industry.

Physicochemical properties and cytotoxicities of Sr-containing biphasic calcium phosphate bone scaffolds

This study demonstrates a new biomaterial system composed of Sr-containing hydroxyapatite (Sr-HA) and Sr-containing tricalcium phosphate (Sr-TCP), termed herein Sr-containing biphasic calcium phosphate (Sr-BCP). Furthermore, a series of new Sr-BCP porous scaffolds with tunable structure and properties has also been developed. These Sr-BCP scaffolds were obtained by in situ sintering of a series of composites formed by casting various Sr-containing calcium phosphate cement (Sr-CPC) into different rapid prototyping (RP) porous phenol formaldehyde resins, which acted as the negative moulds for controlling pore structures of the final scaffolds. Results show that the porous Sr-BCP scaffolds are composed of Sr-HA and Sr-TCP. The phase composition and the macro-structure of the Sr-BCP scaffold could be adjusted by controlling the processing parameters of the Sr-CPC pastes and the structure parameters of the RP negative mould, respectively. It is also found that both the compressive strength (CS) and the dissolving rate of the Sr-BCP scaffold significantly vary with their phase composition and macropore percentage. In particular, the compressive strength achieves a maximum CS level of 9.20 +/- 1.30 MPa for the Sr-BCP scaffold with a Sr-HA/Sr-TCP weight ratio of 78:22, a macropore percentage of 30% (400-550 microm in size) and a total-porosity of 63.70%, significantly higher than that of the Sr-free BCP scaffold with similar porosity. All the extracts of the Sr-BCP scaffold exhibit no cytotoxicity. The current study shows that the incorporation of Sr plays an important role in positively improving the physicochemical properties of the BCP scaffold without introducing obvious cytotoxicity. It also reveals a potential clinical application for this material system as bone tissue engineering (BTE) scaffold.

Paraoxonase status and plasma butyrylcholinesterase activity in chlorpyrifos manufacturing workers

Chlorpyrifos is an organophosphorus (OP) anticholinesterase insecticide. Paraoxonase (PON1) is an enzyme found in liver and plasma that hydrolyzes a number of OP compounds. PON1 polymorphisms include a glutamine (Q)/arginine (R) substitution at position 192 (PON1(Q192R)) that affects hydrolysis of OP substrates, with the PON1(192Q) allotype hydrolyzing chlorpyrifos oxon less efficiently than the PON1(192R) allotype, a variation potentially important in determining susceptibility to chlorpyrifos. We studied 53 chlorpyrifos workers and 60 referents during 1 year and estimated chlorpyrifos exposure using industrial hygiene and employment records and excretion of the chlorpyrifos metabolite 3,5,6-trichloro-2-pyridinol (TCP). Plasma butyrylcholinesterase (BuChE) activity, which may by inhibited by chlorpyrifos exposure, was measured monthly. In addition, plasma samples were assayed for paraoxonase (PONase), diazoxonase (DZOase), and chlorpyrifosoxonase (CPOase) activity to determine PON1 status (inferred genotypes and their functional activity). Linear regression analyses modeled BuChE activity as a function of chlorpyrifos exposure and covariates. We postulated that the level of CPOase activity and the inferred PON1(192) genotype (together reflecting PON1 status) would differ between groups and that PON1 status would modify the models of chlorpyrifos exposure on BuChE activity. Chlorpyrifos workers and referents had a 100-fold difference in cumulative chlorpyrifos exposure. Contrary to our hypotheses, mean CPOase activity was similar in both groups (P=0.58) and PON1(192Q) showed a slight overrepresentation, not an underrepresentation, in the chlorpyrifos group compared with referents (PON1(192QQ), 51% chlorpyrifos, 40% referent; PON(192QR), 43% chlorpyrifos, 40% referent; PON(192RR), 6% chlorpyrifos, 20% referent, P=0.08). In our models, BuChE activity was significantly inversely associated with measures of interim chlorpyrifos exposure, but the biological effects of chlorpyrifos exposure on BuChE activity were not modified by PON1 inferred genotype or CPOase activity.

Are environmental regulations keeping up with innovation? A case study of the nanotechnology industry

Manufactured nanomaterials entered the marketplace of consumer goods in the mid-1990s. With the exception of pending reporting requirements in Canada, no new regulatory requirements have been imposed on the manufacture or use of nanomaterials or their commercial products, although in the past three years governments, industry, and nongovernmental organizations have questioned the need for new regulatory approaches. The debate hinges on whether current scientific information is sufficient for making risk-based decisions, if nanomaterial effects differ from macroscale products, and how much knowledge about potential risk governments should require before products are brought to market. The debate over when and how to regulate manufactured nanomaterials opens the door for a renewed discussion on regulatory environmental policy and suggests that the public may be demanding increased precaution and assurances from government. How government, in concert with industry and the open market, responds will set the bar for future regulations of emerging technologies.

Positive patch-test reactions to platinum are rare

BACKGROUND

Although contact allergy to some metals is common, patch testing for allergy to platinum is rarely performed.

OBJECTIVE

To determine the prevalence of positive patch-test reactions to platinum in an unselected consecutive group of patients presenting for diagnostic patch testing.

METHODS

Unselected patients who presented with a possible diagnosis of contact dermatitis were tested with a series of allergens, including ammonium tetrachloroplatinate 0.25% aqueous.

RESULTS

Of 446 patients tested, only 2 females showed positive reactions to platinum; one had no other positive reactions, and the other had reactions to other metals.

CONCLUSIONS

Positive patch-test reactions to platinum are rare. However, platinum jewelry may occasionally provoke allergic contact dermatitis.

Serum PCB levels and congener profiles among US construction workers

BACKGROUND

The presence of PCB in caulking (sealant) material found in masonry buildings has been well-documented in several countries. A recent investigation of 24 buildings in the greater Boston area found that 8 buildings had high PCB levels in caulking materials used around window frames and in joints between masonry blocks. Workers removing caulking material have been shown to have elevated serum PCB levels.

METHODS

This project compared serum PCB levels among male workers who installed and/or removed PCB-containing caulking material from buildings in the greater Boston area with reference serum PCB levels from 358 men from the same area. Serum PCB levels were measured in the same laboratory by liquid-liquid extraction, column chromatography clean-up and dual capillary column GC/microECD analysis.

RESULTS

When the congener profiles were compared between the reference population and the construction workers, the serum levels of the more volatile, lighter PCBs (di-, tri-and tetrachloro, sum of IUPAC# 6-74) were substantially higher among the construction workers. One of the youngest workers had the lowest total serum PCB levels (sum of 57 congeners) of all 6 workers, but the contribution of more volatile (less chlorinated) PCB congeners (#16, 26,28,33,74,66, and 60) was markedly higher than in other 5 workers and reference men. Only this worker was working on a job that involved removing PCB caulking at the time of the blood sampling.

CONCLUSION

While the results of this pilot study are based upon small numbers (6 construction workers who handled PCB caulking), the serum PCB levels among the construction workers exceed the referents. Comparison of the congener profiles suggests that there are substantial differences between the construction workers and the general population samples. These differences, and the similarities of profiles among the construction workers strongly suggest that occupational contact with caulking material can be a major source of PCB exposure for construction workers.

Protection from physical noxae

Protection from physical noxae must include multiple approaches; physical irritant contact dermatitis develops most likely when the cumulative exposure to several physical factors, such as climatic environmental conditions and friction, pressure or occlusion is given. The additive effect of these conditions, frequently found in modern working environments, not only provokes barrier disturbances, but also inflammatory reactions of the deeper layers of the skin. This review reflects on some examples of occupational physical irritant contact dermatitis (PICD) and the current understanding of its possible pathomechanism. On the one hand, the literature reveals epidemiological studies and case reports and on the other hand murine studies. The combination of both views may permit new insights into the pathogenic mechanisms of PICD and its prevention.

Nanotechnology: the next big thing, or much ado about nothing?

Nanotechnology encompasses an increasingly sophisticated ability to manipulate matter at the nanoscale, resulting in new materials, products and devices that demonstrate new and unusual behaviour. While emerging nanotechnologies have great potential for good, there are increasing concerns that the selfsame attributes that make them attractive will also lead to new risks to human health. Research to date suggests that some purposely made nanomaterials will present hazards based on their structure--as well as their chemistry--thus challenging many conventional approaches to risk assessment and management. People involved in making and using these materials need to know what the risks are and how to manage them, if safe nanotechnology-based businesses are to emerge. Yet the challenges faced by the occupational hygiene community in ensuring safe nano-workplaces are substantial. We currently know enough to suggest that some engineered nanomaterials will present new and unusual risks, but there is very little information on how these risks can be identified, assessed and controlled. And many nanomaterials are in production and use now. Good occupational hygiene practices and existing knowledge on working with hazardous substances provide a useful basis for working safely with nanomaterials. But where existing knowledge fails, new research is needed to fill the gaps: this must be strategically administered and targeted to addressing specific issues in a timely manner. Failing to take these steps will ultimately lead to people's health being endangered and emerging nanotechnologies floundering. However, with foresight, sound science and strategic research, we have the opportunity to ensure that emerging nanotechnologies are as safe as possible, while reaching their full potential.

Exposure, health complaints and cognitive performance among employees of an MRI scanners manufacturing department

PURPOSE

To assess sensory effects and other health complaints that are reported by system testers working near magnetic resonance imaging (MRI) magnets, realizing that it is believed that exposure up to 8 T is safe for humans.

MATERIALS AND METHODS

Levels of exposure to static magnetic fields (SMFs), movement speed during exposure, health complaints, and cognitive performance among employees in an MRI-manufacturing department and at a reference department have been analyzed. Mercury concentrations in urine samples were determined to analyze whether they depend on exposure to SMFs.

RESULTS

Average exposure of system testers was 25.9 mT/8 hours at a 1.0-T system and 40.4 mT/8 hours at a 1.5-T system. Vertigo, metallic taste, and concentration problems were more reported among workers of MRI-fabrication than in the reference department. Cognitive performance was tested outside the SMF, and no significant changes were detected.

CONCLUSION

This study suggests that any effects on cognitive functions are acute and transient and disappear rapidly after exposure has ended. All complaints, except for headaches, were more frequently reported by "fast movers" than by "slow movers," and depended on field strength and duration of exposure. Mercury-levels in urine were not affected.

Patch-test reactions to thioureas are frequently relevant

BACKGROUND

Thioureas are used as antioxidants in the manufacture of rubber (especially neoprene) and as fixatives in photography and photocopy paper. The number of reported cases of allergic contact dermatitis from thioureas is relatively low, and standard patch test series often do not contain thiourea allergens. Thioureas are included in our institution's standard patch test series.

OBJECTIVE

To examine the occurrence and relevance of patch-test reactions to thioureas.

METHODS

We retrospectively analyzed patch-test data for patients evaluated between January 1999 and June 2001. Patients included in the study underwent testing with a standard screening series of allergens and a standardized patch testing technique. Our standard patch test series includes mixed dialkyl thioureas at a concentration of 1% in petrolatum.

RESULTS

Of 1,368 patients tested with our standard series, 33 patients (2.4%) had patch-test reactions to mixed dialkyl thioureas at day 5. Reactions in 14 (42%) of those patients were of definite clinical relevance, indicating a confirmed exposure to thioureas in many different settings.

CONCLUSION

Patch-test reactions to thioureas occur as often as do reactions to many other allergens in the standard series and are often relevant. Institutions should consider including mixed dialkyl thioureas in their standard patch test screening series.

Prolonged menstrual cycles in female workers exposed to ethylene glycol ethers in the semiconductor manufacturing industry

BACKGROUND

It has been shown that female workers exposed to ethylene glycol ethers (EGEs) in the semiconductor industry have higher risks of spontaneous abortion, subfertility, and menstrual disturbances, and prolonged waiting time to pregnancy.

AIMS

To examine whether EGEs or other chemicals are associated with long menstrual cycles in female workers in the semiconductor manufacturing industry.

METHODS

Cross-sectional questionnaire survey during the annual health examination at a wafer manufacturing company in Taiwan in 1997. A three tiered exposure-assessment strategy was used to analyse the risk. A short menstrual cycle was defined to be a cycle less than 24 days and a long cycle to be more than 35 days.

RESULTS

There were 606 valid questionnaires from 473 workers in fabrication jobs and 133 in non-fabrication areas. Long menstrual cycles were associated with workers in fabrication areas compared to those in non-fabrication areas. Using workers in non-fabrication areas as referents, workers in photolithography and diffusion areas had higher risks for long menstrual cycles. Workers exposed to EGEs and isopropanol, and hydrofluoric acid, isopropanol, and phosphorous compounds also showed increased risks of a long menstrual cycle.

CONCLUSIONS

Exposure to multiple chemicals, including EGEs in photolithography, might be associated with long menstrual cycles, and may play an important role in a prolonged time to pregnancy in the wafer manufacturing industry; however, the prevalence in the design, possible exposure misclassification, and chance should be considered.

Occupational health education and collaboration for reducing the risk of lead poisoning of workers in a battery manufacturing plant in Thailand

We provided occupational health education as training to all workers (N=31) and managers, and collaborated with them against reducing the risk of lead poisoning of workers at an assembly section in a battery manufacturing plant in Bangkok, Thailand in 2002. After occupational health education, many workers (80.6-100.0%) noticed and understood the toxicity of lead and the importance of protection against it. Many workers regularly wore long sleeved shirt and trousers, and used the appropriate mask all day long. They changed the attitude toward their work and improved personal hygiene, for example no smoking in the workplace, washing their hands by a detergent before drinking water or having lunch, and taking a bath after the work. They especially took off working clothes at an office outside the workplace and washed them everyday. The average blood lead level of the workers significantly (P=0.002) reduced from 32.7 microg/dl to 22.4 microg/dl, although airborne lead level in the workplace remained unchanged with before conditions. From these results occupational health education and collaboration between workers and managers were effective tools to reduce the risk of lead poisoning of workers in a battery manufacturing plant.

Impact of Manufacturing Technology and Material Composition on the Clinical Performance of Hydrogel Lenses

PURPOSE

To establish the clinical impact of three different methods of manufacture used to produce soft contact lenses.

METHODS

Clinical performance of five lens types was investigated by undertaking a prospective, double-masked, randomized, crossover study. Three of the lenses were made from poly(hydroxyethyl methacrylate) (pHEMA) by three different manufacturing processes (lathing, spin casting, and cast molding), and the remaining two lenses were cast molded from different materials-hydroxyethyl methacrylate/methacrylic acid and hydroxyethyl methacrylate/glycerol methacrylate (HEMA/GMA). All lenses were specially fabricated for this work at the same manufacturing plant. Thirty-four soft contact lens wearers wore each lens for 1 month on a daily-wear basis. Several clinical variables, such as ocular response, visual acuity, lens fitting, prelens tear film, lens surface dehydration, subjective response, and protein deposition, were measured.

RESULTS

In general, the spun-cast pHEMA lens performed inferiorly compared with the other pHEMA lenses. This lens induced significantly more limbal and conjunctival hyperemia than the cast-molded lens and provided poorer low contrast visual acuity (LCVA) than the other two lenses. It dehydrated more and had the least on-eye movement. However, the spun-cast lens deposited the least protein of the pHEMA lenses. In general, the HEMA/GMA lens performed inferiorly compared with the other cast-molded lenses. LCVA was worse with this lens, and subjective responses showed that this lens was thought to give the worst visual performance of the cast-molded lenses. It was also thought to be the most difficult lens to handle. Significantly more breakages occurred with this lens than any other.

CONCLUSIONS

Overall, this work has shown that manufacturing method and material composition have a fundamental effect on many clinical properties of a lens. Therefore, method of manufacture is also an important consideration in the overall production of a soft lens.

Biological evaluation of hydroxyapatite/poly-L-lactide (HAp/PLLA) composite biomaterials with poly-L-lactide of different molecular weights intraperitoneally implanted into mice

Histopathologic analysis of the tissue with HAp/PLLA implants was made and the leukocyte formula and chemiluminescence response of peritoneal phagocytes 2, 7 and 12 weeks after intraperitoneal implantation studied. Implants were made of HAp/PLLA biocomposites with PLLA molecular weights of 50000 (HAp/PLLA(50)) and 430000 g/mol (HAp/PLLA(430)) and of crushed devitalized femur bone of a young Wistar rat. Leukocyte formula and chemiluminescence of peritoneal phagocytes showed no systemic inflammatory response. The studied implants caused locally weak inflammatory reaction. The resorption of implants ranges in intensity (polymer resorption, i.e. disappearance rate), from the highest with the bone implants, low with HAp/PLLA(50), to the lowest with the HAp/PLLA(430) implants. Good resorption of the biocomposites and its mutual ingrowth with connective tissue prove their good biocompatibility.

Experimental proof of contamination of blood components by (1?3)-?-D-glucan caused by filtration with cellulose filters in the manufacturing process

The level of (1-->3)-beta-D-glucan in blood is a diagnostic index of fungal infection because it is released from the fungal cell wall. However, high levels of plasma (1-->3)-beta-D-glucan in patients administered blood components may give false positive results. High levels of (1-->3)-beta-D-glucan have been detected in blood components. We suspected that (1-->3)-beta-D-glucan from cellulose filters had been eluted into blood components by filtration in the manufacturing process. To investigate the contamination of blood components by (1-->3)-beta-D-glucan from cellulose filters, in vitro experiments were performed by using six cellulose filters and a nylon filter. Human serum albumin (HSA) solution (100 ml) was flowed through each filter after rinsing with 100 ml of distilled water, and (1-->3)-beta-D-glucan in each fraction was determined by Fungitec G test MK. The concentration of (1-->3)-beta-D-glucan eluted from cellulose filters in 100-ml distilled water fractions ranged from 6 to 207 pg/ml, and that of HSA fractions ranged from 33 to 20,784 pg/ml. These data showed that remarkably higher (1-->3)-beta-D-glucan levels were detected in HSA fractions flowed through cellulose filters in spite of advance rinsing with 100 ml of distilled water. In the case of a nylon filter, (1-->3)-beta-D-glucan was not eluted in either fraction. These results indicate that (1-->3)-beta-D-glucan contamination in blood components is caused by filtration with cellulose filters in the manufacturing process.

Synthetic bedding and wheeze in childhood

BACKGROUND

The reasons for the increase in childhood asthma over time are unclear. The indoor environment is of particular concern. An adverse role for synthetic bedding on asthma development in childhood has been suggested by cross-sectional studies that have found an association between synthetic pillow use and childhood wheeze. Prospective data on infant bedding have not been available.

METHODS

Bedding data at 1 month of age were available from an infant survey for children who were participating in a 1995 follow-up study (N = 863; 78% traced). The 1995 follow-up was embedded in a larger cross-sectional survey involving 6,378 seven year olds in Tasmania (N = 92% of eligible). Outcome measures included respiratory symptoms as defined in the International Study of Asthma and Allergies in Childhood protocol. Frequent wheeze was defined as more than 12 wheeze episodes over the past year compared with no wheeze.

RESULTS

Synthetic pillow use at 1 month of age was associated with frequent wheeze at age 7 (adjusted relative risk [aRR] = 2.5; 95% confidence interval [CI] = 1.2-5.5) independent of childhood exposure. Current synthetic pillow and quilt use was strongly associated with frequent wheeze (aRR = 5.2; CI = 1.3-20.6). Substantial trends were evident for an association of increasing number of synthetic bedding items with frequent wheeze and with increasing wheeze frequency. Among children with asthma, the age of onset of asthma occurred earlier if synthetic bedding was used in infancy.

CONCLUSIONS

In this cohort, synthetic bedding was strongly and consistently associated with frequent childhood wheeze. The association did not appear to be attributable to bedding choice as part of an asthma management strategy.

Stipatosis or hypersensitivity pneumonitis caused by esparto (Stipa tenacissima) fibers

Hypersensitivity pneumonitis or extrinsic allergic alveolitis may be defined as an immunological pulmonary disease caused by a variety of antigens reaching the lungs through inhaled organic and inorganic dusts derived from different sources, although they are usually occupational. Farmer's lung and pigeon breeder's lung are probably the most well-known types of hypersensitivity pneumonitis worldwide. Esparto grass (Stipa tenacissima), which is a grammineous plant which is commonly found in the Mediterranean countries, has a wide variety of uses. Esparto fiber is used for the manufacturing of ropes, hemp sandals, rush mats and parkets; for decorative stucco plates, used on walls and ceilings. Esparto supports a large industry in Spain. The first reports referring to esparto dust as a cause of respiratory disease did not appear until the 1960s, and it was first described as a byssinosis-like disorder. The first cases reported, in which immunologic and challenge tests were used to confirm this association, were described 14 years ago and referred as hypersensitivity pneumonitis nominated as stipatosis. Later, a large number of cases of esparto dust-induced hypersensitivity pneumonitis were reported by different authors, so that esparto may be nowadays considered as the main substance causing extrinsic allergic alveolitis in Spain. Afumigatus has been revealed to be the main inducing cause of stipatosis but probably is not the only one since other microorganisms could be implicated. On the other hand esparto fibers may also cause occupational asthma. In this article the prominent clinical findings of this disease as well as the results of serologic, bronchoalveolar lavage (BAL) and specific inhalation tests are shown. A complete historical review of esparto-induced allergic respiratory disease is also described.

Long man-made fibers and lung cancer risk

We show that available experimental data from long-term oncogenicity experiments in Fisher rats are consistent with the hypothesis that the oncogenic potential of long man-made mineral fibers is determined mainly by their biopersistence. We present analyses of these data within the initiation-promotion-progression paradigm of carcinogenesis. Our method of analysis can take the temporal pattern of the burden of long fibers in the lungs of individual animals into explicit account. For this analysis, the temporal pattern of lung burden for each animal was imputed from the information obtained from sacrificed animals. The data are consistent with the hypothesis that fibers act as initiators in the rat lung. We present an estimate of the dose-dependent initiation parameter that is based on all the available data.

Solvent exposures at shoe factories and workshops in Hebron City, West Bank

Exposure to organic solvents has been reported to increase the risks for acute and chronic health effects among shoe industry workers. In developing countries, protection against chemical exposures is often not provided. The study was conducted to identify working conditions and estimate the concentrations of organic solvents used in shoe factories and workshops in Hebron City. Personal interviews containing questions related to personal protective equipment (PPE) were used to identify working conditions, and samples collected from factories and workshops were analyzed using gas chromatography. Geometric means (GMs) were calculated for the solvents. Six major organic solvents were detected in the factories. Acetone (GM = 51.5 mg/m3, GSD = 3.82) was common in gluing tasks. Dichloromethane (GM = 47 mg/m3, GSD = 2.62) was common in cleaning tasks. Heptane, methylethyl ketone, n-hexane, and toluene were common in gluing tasks. Four major organic solvents were detected in the workshops: acetone (GM = 32.3 mg/m:3, GSD = 6.33), toluene (GM = 70.3 mg/m3, GSD = 3.06), n-hexane (GM = 19.4 mg/m3:, GSD = 2.65), and methylethyl ketone (GM = 130 mg/mM3, GSD = 1.5). 81% of the factory workers had never used respiratory protective equipment, and 92% had never used work clothes. 97% of the workers in the workshops had never used respiratory protective equipment, 94% had never worn gloves, and 90% had never used work clothes. Exposures to solvents in the absence of personal Protective equipment, tasks barriers, and mechanical ventilation can adversely affect health.

An occupational risk survey of a refractory brick company in Ha Noi, Viet Nam

Viet Nam has an increasing need for building materials, including refractory bricks. Little is known regarding the occupational hazards incurred in brick manufacturing. To determine the occupational health hazards posed by a refractory brick operation in Ha Noi, Viet Nam, a cross-sectional occupational risk survey was conducted, focusing on respirable dust hazards. It included an industrial hygiene walk-through and gravimetric dust analysis. Noise, heat, lack of head protection, and dust exposure were hazards identified at the brick-manufacturing site. Respiratory protection involved a three-layer cloth mask that had not been tested for efficacy. Silica dust exposure levels exceeded the Vietnamese permissible exposure level by almost fivefold based on gravimetric assessment and estimated silica content. This brick manufacturing site contains significant injury and respiratory illness hazards. Further investigations are necessary to begin to develop occupational safety measures at the site.

Interspecies comparisons of the toxicity of asbestos and synthetic vitreous fibers: a weight-of-the-evidence approach

This analysis reviews the available literature on interspecies comparisons of the toxicity of asbestos and synthetic vitreous fibers (SVFs). This topic is of substantial practical importance because most quantitative risk analyses on the effects of inhalation of SVFs are based upon extrapolation of data from rodent inhalation studies. Available information on interspecies comparisons for both dosimetry (the relation between exposure concentration and fiber lung burden) and potency (the relation between lung burden and disease) is summarized. Dosimetry models indicate that, on a normalized basis, fiber deposition and clearance rates are lower in humans than rats. Potency is less well understood than dosimetry, in part because the source of relevant human data is asbestos studies, which are adequate to demonstrate hazard, but are problematic in other regards. There are significant interspecies differences between the mouse, hamster, rat, and human. The available evidence suggests that the rat is preferable as a model for the human. Rats develop fibrosis at comparable lung burdens [10(6) long (> 20 microm length) fibers per gram of dry lung] to those in humans. This analysis concludes that, on a weight-of-evidence basis, there is no reason to conclude that humans are more sensitive to fibers than rats with respect to the development of lung cancer.

Asbestos and man-made vitreous fibers as risk factors for diffuse malignant mesothelioma: results from a German hospital-based case-control study

BACKGROUND

This study examines the role of occupational factors in the development of diffuse malignant mesothelioma with special emphasis on the dose-response relationship for asbestos and on the exposure to man-made vitreous fibers (MMVFs).

METHODS

One hundred and twenty-five male cases, diagnosed by a panel of pathologists, were personally interviewed concerning their occupational and smoking history. The same number of population controls (matched for sex, age and region of residence) underwent similar interviews by trained interviewers. Odds ratios (OR) were calculated for an expert-based exposure index using conditional logistic regression.

RESULTS

Exposure to asbestos shows the expected sharp gradient with an OR of about 45 for a cumulative exposure > 1.5 fiber years (arithmetic mean 16 fiber years). A significant OR was calculated even for the lowest exposure category "> 0 - < or = 0.15 fiber years". Although the mean cumulative exposure to MMVF is roughly 10% of the exposure to asbestos, an increased OR is observed in an ever/never evaluation. This observation is heavily hampered by methodical problems. A corresponding case-control study was performed using a lung tissue fiber analysis in addition to interviews. Both interviews and the lung tissue analysis yielded similar OR levels between the reference and the maximum exposure intervals.

CONCLUSIONS

Despite a possible influence as a result of selection and information bias, our results confirm the previously reported observation of a distinct dose-response relationship even at levels of cumulative exposure below 1 fiber year. Moreover, the study confirms that asbestos is a relevant confounder for MMVF. A causal relationship between exposure to MMVF and mesothelioma could neither be detected nor excluded, as in other studies.

Human volunteer studies; a consumer products company view

The term 'contact dermatitis' refers to a range of adverse effects whose causation is quite varied. Manufacturers of consumer products have an important responsibility to minimise the extent to which their products cause such skin reactions. In meeting this responsibility, use may be made of humans, e.g. in studies related to skin irritation, to try to ensure the highest possible safety standards are achieved. The purpose of this short review paper is to outline the principles that must be followed before initiating studies with human volunteers. In addition, these principles are considered in the context of European legislation on chemicals and preparations.