Bladder cancer incidence among workers exposed to o-toluidine, aniline and nitrobenzene at a rubber chemical manufacturing plant

The face behind the Covid-19 mask - A comprehensive review

The threat of epidemic outbreaks like SARS-CoV-2 is growing owing to the exponential growth of the global population and the continual increase in human mobility. Personal protection against viral infections was enforced using ambient air filters, face masks, and other respiratory protective equipment. Available facemasks feature considerable variation in efficacy, materials usage and characteristic properties. Despite their widespread use and importance, face masks pose major potential threats due to the uncontrolled manufacture and disposal techniques. Improper solid waste management enables viral propagation and increases the volume of associated biomedical waste at an alarming rate. Polymers used in single-use face masks include a spectrum of chemical constituents: plasticisers and flame retardants leading to health-related issues over time. Despite ample research in this field, the efficacy of personal protective equipment and its impact post-disposal is yet to be explored satisfactorily. The following review assimilates information on the different forms of personal protective equipment currently in use. Proper waste management techniques pertaining to such special wastes have also been discussed. The study features a holistic overview of innovations made in face masks and their corresponding impact on human health and environment. Strategies with SDG3 and SDG12, outlining safe and proper disposal of solid waste, have also been discussed. Furthermore, employing the CFD paradigm, a 3D model of a face mask was created based on fluid flow during breathing techniques. Lastly, the review concludes with possible future advancements and promising research avenues in personal protective equipment.

Occurrence of microplastics in commercial marine dried fish in Asian countries

The major risk of microplastics in marine environments is the bioaccumulation in marine organisms. Plastic ingestion by marine organisms has been investigated and recently more attention has been given to microplastics in seafood. However, it is seldom reported the occurrence of microplastics in marine commercial dried fish products available for human consumption. Here, we report the occurrence of microplastics in 14different marine dried fish products from seven Asian countries. Microplastics were observed in most dried fish, with fibers representing ~80% of the total-microplastics. The major plastic polymers, identified using Micro-Raman spectroscopy, included polyethylene (35%), polyethylene terephthalate (26%), polystyrene (18%), polyvinyl chloride (12%), and polypropylene (9%). The highest count, in either per individual (1.92 ± 0.12) or per gram of dried fish (0.56 ± 0.03), were found in Etrumeus micropus from Japan. Marine dried fish, which are typically eaten whole, may contribute to the ingestion of microplastics by humans, posing potential health risks especially in Asian countries. Further studies are needed to identify the occurrence of smaller sized microplastics and nanoplastics and their potential health impacts.

Risk assessment for o-toluidine and bladder cancer incidence

BACKGROUND

Elevated bladder cancer incidence has been reported in a cohort of 1875 workers manufacturing chemicals used in the rubber industry and employed any time during 1946-2006. o-Toluidine (OT), an aromatic amine, was the prime suspect agent. Using the available environmental data and process characterization, previous investigators assigned ranks to volatile chemical air concentrations across time in departments and jobs, reflecting probabilities of exposure and use of personal protective equipment for airborne and dermal exposures. Aniline, another aromatic amine, was present at comparable concentrations and is known to be an animal carcinogen but produced lower levels in post-shift urine and of hemoglobin adducts than OT in a group of workers.

METHODS

A quantitative risk assessment was performed based on this same population. In this study, cumulative OT exposures were estimated (a) based on previously assigned ranks of exposure intensity and reported actual exposures in jobs with the highest assigned rank, and (b) directly from the historical environmental sampling for OT. Models of bladder cancer incidence were evaluated taking into account possible healthy worker survivor effects.

RESULTS

Under various assumptions regarding workforce turnover, the excess lifetime risk of bladder cancer from OT exposure at 1 ppb was estimated to be in the range 1-7 per thousand.

CONCLUSIONS

The current ACGIH TLV and OSHA standards for OT are 2 and 5 ppm, respectively, 1000-fold higher than the exposure estimated here for 1-7 per thousand excess lifetime risk.

Why We Will Continue to Lose Our Battle with Cancers If We Do Not Stop Their Triggers from Environmental Pollution

Besides our current health concerns due to COVID-19, cancer is a longer-lasting and even more dramatic pandemic that affects almost a third of the human population worldwide. Most of the emphasis on its causes has been posed on genetic predisposition, chance, and wrong lifestyles (mainly, obesity and smoking). Moreover, our medical weapons against cancers have not improved too much during the last century, although research is in progress. Once diagnosed with a malignant tumour, we still rely on surgery, radiotherapy, and chemotherapy. The main problem is that we have focused on fighting a difficult battle instead of preventing it by controlling its triggers. Quite the opposite, our knowledge of the links between environmental pollution and cancer has surged from the 1980s. Carcinogens in water, air, and soil have continued to accumulate disproportionally and grow in number and dose, bringing us to today's carnage. Here, a synthesis and critical review of the state of the knowledge of the links between cancer and environmental pollution in the three environmental compartments is provided, research gaps are briefly discussed, and some future directions are indicated. New evidence suggests that it is relevant to take into account not only the dose but also the time when we are exposed to carcinogens. The review ends by stressing that more dedication should be put into studying the environmental causes of cancers to prevent and avoid curing them, that the precautionary approach towards environmental pollutants must be much more reactionary, and that there is an urgent need to leave behind the outdated petrochemical-based industry and goods production.

Risk of bladder cancer in male Japanese workers exposed to ortho-toluidine and other aromatic amines

PURPOSE

Nine bladder cancer (BCa) cases were reported among aromatic amine-exposed male workers at a factory manufacturing organic dye/pigment intermediates in Japan. We aimed to evaluate the characteristics of aromatic amine-exposed workers by cross-sectional observation, and the risk of BCa by assessing the standardized incidence ratio (SIR).

METHODS

In the cross-sectional study, our subjects were: 9 BCa patients, 36 aromatic amine-exposed non-patients, and 79 non-exposed workers from 3 factories. We evaluated the subjects' medical history, urinalysis, qualitative determination of nuclear matrix protein 22, and urinary cytology. For SIR assessment, 98 aromatic amine-exposed workers from 1 factory were included, and the Japanese general male population was used as a referent population. Since no direct aromatic amine-exposure data were available, we calculated surrogate exposure levels using information on job sites, exposure potency, and duration.

RESULTS

Coexistent aromatic amines were ortho-toluidine (OT), aniline, para-toluidine, ortho-anisidine, 2,4-xylidine, and ortho-chloroaniline. The prevalence rates of cystitis and bladder lesion-related symptoms in both BCa patients and aromatic amine-exposed non-patient workers were significantly higher than those of non-exposed workers. Overall, the SIR for BCa in OT-exposed workers was 56.8 (95% CI 27.7-104.3) and apparent dose-response relationships were revealed between the SIR and the surrogate exposure level in the 0-10-year lagged analyses. Overall, SIRs in other aromatic amine-exposed workers were also significantly high but no or unclear dose-response relationships were observed.

CONCLUSIONS

We conclude that OT may be responsible for the increased risk of BCa. Regular monitoring of bladder lesion-related symptoms is essential for the early identification of BCa.

Are electronic cigarettes and vaping effective tools for smoking cessation? Limited evidence on surgical outcomes: a narrative review

The rising popularity of e-cigarettes and vaping, particularly in youth populations, has prompted the scientific community to ocassionally recommend their use as alternative to smoking or as a modality for smoking cessation. Media also tends to portray them as stylish, smoking cessation tools. We first studied the current literature to better understand whether they are viable options for surgeons to use prior to surgery as part of their armamentarium and their efficacy in attaining smoking abstinence. Next, we performed a comprehensive review of the literature to study the impact of e-cigarette and vaping on lung pathophysiology, surgical outcomes, and postoperative complications. After a thorough search, we found limited evidence suggesting that e-cigarettes and vaping are effective smoking cessation tools, and indeed may increase the propensity of dual smoking, contrary to e-cigarette advertisements. Many potential biases and limitations exist due to self-reporting when investigating e-cigarettes and vaping. While there is controversial data in the literature about e-cigarettes and vaping not leading to lung cancer, there are chemicals in these products that compromise lung hemostasis, negatively affect the immune system, and have detrimental inflammatory effects on wound healing. Studies are warranted to elucidate objective data regarding short and long-term effects of these products on surgical outcomes, and given the current data, they should not be utilized as viable smoking cessation tools.

Cancer and noncancer mortality among aluminum smelting workers in Badin, North Carolina

BACKGROUND

Badin, North Carolina, hosted an aluminum smelting plant from 1917 to 2007. The Concerned Citizens of West Badin reported suspected excess cancer mortality among former employees. This study aimed to investigate these concerns.

METHODS

The study cohort was enumerated from United Steel Workers' records of workers employed from 1980 to 2007. Cause-specific mortality rates in the cohort were compared with North Carolina population mortality rates using standardized mortality ratios (SMRs), standardized by age, sex, race, and calendar period. We estimated cause-specific adjusted standardized mortality ratios (aSMRs) using negative controls to mitigate healthy worker survivor bias (HWSB). Standardized rate ratios (SRRs) were calculated to compare mortality rates between workers ever employed vs never employed in the pot room.

RESULTS

All-cause mortality among Badin workers was lower than in the general population (SMR: 0.81, 95% confidence interval [CI]: 0.71-0.92). After adjusting for HWSB, excesses for all cancers (aSMR: 1.55, 95% CI: 1.10-2.21), bladder cancer (3.47, 95% CI: 1.25-9.62), mesothelioma (17.33, 95% CI: 5.40-55.59), and respiratory cancer (1.24, 95% CI: 0.77-1.99) were observed. Black males worked the highest proportion of their employed years in the pot room. Potroom workers experienced higher respiratory cancer (SRR: 2.99, 95% CI: 1.23-7.26), bladder cancer (SRR: 1.58, 95% CI: 0.15-15.28), and mesothelioma (SRR: 3.36, 95% CI: 0.21-53.78) mortality rates than never workers in the pot room.

CONCLUSIONS

This study responds to concerns of a group of former aluminum workers. The results, while imprecise, suggest excess respiratory and bladder cancers among pot room workers in a contemporary cohort of union employees at a US smelter.

Comparative γ-H2AX analysis for assessment of the genotoxicity of six aromatic amines implicated in bladder cancer in human urothelial cell line

Recently, it was reported that ten cases of bladder cancer occurred among employees, who handled several kinds of aromatic amines, at a Japanese chemical plant. The common aromatic amines were identified as ortho-toluidine, para-toluidine, aniline, ortho-chloroaniline, ortho-anisidine, and 2,4-dimethylaniline. All of these aromatic amines, except ortho-chloroaniline, have been found to be carcinogenic in animals and/or humans. Genotoxic events are known to be crucial steps in the initiation of cancer; information on the genotoxicity of these aromatic amines is insufficient and consistent results have not been obtained. In this study, we examined the genotoxicity of the six different aromatic amines associated with bladder cancer by assessing phosphorylated histone H2AX (γ-H2AX) in a cultured human urothelial cell line, 1T1. We showed that all six aromatic amines generated γ-H2AX. In addition, the γ-H2AX-inducing potential of these six aromatic amines was distinctly different; ortho-chloroaniline and 2,4-dimethylaniline showed particularly high potential, followed by ortho-toluidine, ortho-anisidine, para-toluidine ≒ aniline. The findings of this study may provide important information for the risk assessment of chemicals and for interpreting epidemiological studies on occupational bladder cancer.

Selective extraction and determination of aromatic amine metabolites in urine samples by using magnetic covalent framework nanocomposites and HPLC-MS/MS

Purification and selective enrichment of ultra-low level metabolites in bio-samples is very important for HPLC-MS/MS analysis. A magnetic covalent organic framework (i.e. COFs) (TpPa-1) (i.e. 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde-p-phenylenediamine) material was synthesized and used for a magnetic solid phase extraction (MSPE) method in aromatic amine (AA) metabolites (i.e. 1-naphthylamine, 2-naphthylamine, 3-aminobiphenyl and 4-aminobiphenyl) in urine, and then HPLC-MS/MS was employed for analysis. The morphology, pore structure, surface area, chemical composition, magnetic properties, and thermal stability of the synthesized magnetic COFs were characterized with several analysis techniques, such as nitrogen adsorption–desorption isotherms, HRTEM, FTIR, XRD, and so on. MSPE conditions were optimized and analytical performance of the developed method was characterized. The limit of detection (LOD) and limit of quantification (LOQ) of four AAs ranged from 0.01 to 0.07 ng mL⁻¹ and 0.04 to 0.22 ng mL⁻¹, respectively. The recoveries of 1-NA, 2-NA, 3-ABP, 4-ABP were in the range of 81.9–105%, 87.8–102%, 101–120%, 88.3–117%, respectively. Good intra-day and inter-day precision were obtained with RSD of less than 5.8% and 9.9%, respectively. Furthermore, the synthesized magnetic COFs absorbent could be recycled in MSPE at least 5 times. Analytical results of AA metabolites in real urine samples with the developed method showed significant difference (p < 0.01) between smokers and nonsmokers. Thus, urinary AA metabolites could be exposure biomarkers for cigarette smoke.

Purification and selective enrichment of ultra-low level metabolites in bio-samples is very important for HPLC-MS/MS analysis.

Amphiphilic calix[4]arenes as a highly selective gas chromatographic stationary phase for aromatic amine isomers

Efficient separation of aromatic amine isomers is a challenging issue in chemical industry and environmental analysis. Here we report the use of p-amino-tetradecyloxy-calix[4]arene (C4A-NH₂) as a novel stationary phase for gas chromatographic (GC) separations. The statically coated C4A-NH₂ capillary column showed a high column efficiency of 4332 plates/m for a 0.25 mm ID column and medium polarity. The C4A-NH₂ stationary phase exhibited an excellent separation performance both for aromatic amine isomers and a complex mixture of aliphatic analytes with a wide ranging polarity, showing distinct advantages over the commercial polysiloxane stationary phases via diversified molecular interactions covering H-bonding, π-π, van der Waals interactions and shape-fitting selectivity. The retention mechanisms of aromatic amine isomers on C4A-NH₂ column were further investigated by quantum chemistry calculations. In addition, the C4A-NH₂ column showed good column repeatability with relative standard deviation (RSD) values of 0.03%-0.07% for run-to-run, 0.10%-0.27% for day-to-day and 2.6%-5.7% for column-to-column, respectively, and thermal stability up to 240℃.

Antioxidants and selenocompounds inhibit 3,5-dimethylaminophenol toxicity to human urothelial cells

Exposure to alkyl anilines may lead to bladder cancer, which is the second most frequent cancer of the urogenital tract. 3,5-dimethylaniline is highly used in industry. Studies on its primary metabolite 3,5-dimethylaminophenol (3,5-DMAP) showed that this compound causes oxidative stress, changes antioxidant enzyme activities, and leads to death of different mammalian cells. However, there is no in vitro study to show the direct effects of 3,5-DMAP on human bladder and urothelial cells. Selenocompounds are suggested to decrease oxidative stress caused by some chemicals, and selenium supplementation was shown to reduce the risk of bladder cancer. The main aim of this study was to investigate whether selenocompounds organic selenomethionine (SM, 10 µmol/L) or inorganic sodium selenite (SS, 30 nmol/L) could reduce oxidative stress, DNA damage, and apoptosis in UROtsa cells exposed to 3,5-DMAP. 3,5-DMAP caused a dose-dependent increase in intracellular generation of reactive oxygen species, and its dose of 50 µmol/L caused lipid peroxidation, protein oxidation, and changes in antioxidant enzyme activities in different cellular fractions. The comet assay also showed single-strand DNA breaks induced by the 3,5-DMAP dose of 50 µmol/L, but no changes in double-strand DNA breaks. Apoptosis was also triggered. Both selenocompounds provided partial protection against the cellular toxicity of 3,5-DMAP. Low selenium status along with exposure to alkyl anilines can be a major factor in the development of bladder cancer. More mechanistic studies are needed to specify the role of selenium in bladder cancer.

British rubber and cable industry cohort: 49-year mortality follow-up

BACKGROUND

The International Agency for Research on Cancer (IARC) has determined there is sufficient evidence that working in the rubber manufacturing industry increases the risk of cancers of the stomach, lung, bladder and leukaemia and lymphoma.

OBJECTIVES

To examine mortality patterns of a prospective cohort of men from the rubber and cable manufacturing industries in Great Britain.

METHODS

SMRs were calculated for males aged 35+ years at start of follow-up in 1967-2015 using the population of England and Wales as the external comparator. Tests for homogeneity and trends in SMRs were also completed.

RESULTS

For all causes, all malignant neoplasms, non-malignant respiratory diseases and circulatory diseases, SMRs were significantly elevated, and also particularly for cancers of the stomach (SMR=1.26,95% CI 1.18 to 1.36), lung (1.25,95% CI 1.21 to 1.29) and bladder (1.16,95% CI 1.05 to 1.28). However, the observed deaths for leukaemia, non-Hodgkin's lymphoma (NHL) and multiple myeloma were as expected. Bladder cancer risks were elevated only in workers exposed to antioxidants containing 1-naphthylamine and 2-naphthylamine.

CONCLUSIONS

This study provides evidence of excess risks in the rubber industry for some non-cancer diseases and supports IARC's conclusions in relation to risks for cancers of the bladder, lung and stomach, but not for leukaemia, NHL or multiple myeloma.

An epidemic of bladder cancer: ten cases of bladder cancer in male Japanese workers exposed to ortho-toluidine

Background:

ortho-Toluidine (OT) was listed as a Group 1 carcinogen by the International Agency for Research on Cancer in 2012 based on epidemiological observations of workers co-exposed to OT and aromatic amines. From 2014 to 2017, several cases of bladder cancer (BCa) secondary to occupational exposure, primarily to OT, were detected in Japan.

Objective:

To describe 10 cases of BCa in male Japanese workers exposed primarily to OT at two plants that produce organic dye and pigment intermediates.

Methods:

Details of the 10 cases were obtained from company records and through a questionnaire and interview. The surrogate level of exposure to each aromatic amine was calculated as the total job-weight/month for each process for each job-year.

Results:

No quantitative exposure data were available. In most cases the surrogate level of exposure to OT was higher than to other amines. All 10 cases were exposed primarily to OT and co-exposed to para-toluidine, ortho-anisidine, aniline, 2,4-xylidine or ortho-chloroaniline. The age range at diagnosis was 41-71 years (mean 56). The duration of OT exposure was 7-28 years (mean 16.5). Disease latency was 16-28 years (mean 21.9). Eight patients were smokers. The main symptom at diagnosis was hematuria (70%).

Conclusions:

The characteristics of BCa cases were associated with a high surrogate level of OT exposure and a disease latency of more than 20 years from the initial OT exposure. The main route of OT exposure was likely through the skin. It is necessary to continue health examinations in these target groups.

Comparison of Bladder Carcinogens in the Urine of E-cigarette Users Versus Non E-cigarette Using Controls

Electronic cigarette (EC) use is gaining popularity as a substitute for conventional smoking due to the perception and evidence it represents a safer alternative. In contrast to the common perception amongst users that ECs represent no risk initial studies have revealed a complex composition of e-cigarette liquids. Conventional cigarette smoking is a known risk factor for developing bladder cancer and prior reports raise concern some of those causative compounds may exist in EC liquids or vapor. Urine samples were collected from 13 e-cigarette using subjects and 10 non e-cigarette using controls. Five known bladder carcinogens that are either present in conventional cigarettes, products of combustion, or solvents believed to be used in some e-cigarette formulations were quantified by liquid chromatography – mass spectrometry (LC-MS). Analysis of e-cigarette user urine revealed the presence of two carcinogenic compounds, o-toluidine and 2-naphthylamine, at a mean 2.3 and 1.3 fold higher concentration (p-value of 0.0013 and 0.014 respectively). Many of these subjects (9/13) were long term nonsmokers (>12 months). Further study is needed to clarify the safety profile of e-cigarettes and their contribution to the development of bladder cancer given the greater concentration of carcinogenic aromatic amines in the urine of e-cigarette users.

Urine cytology screening of French workers exposed to occupational urinary tract carcinogens: a prospective cohort study over a 20-year period

OBJECTIVES

To demonstrate that urine cytology screening can provide relevant epidemiological data for earlier detection of urothelial cancer caused by occupational exposure.

DESIGN

Prospective cohort study.

SETTING

Industries using urothelial carcinogens in France. Urine samples were collected on site, after a work week and were analysed at the University Hospital of Clermont-Ferrand, France.

PARTICIPANTS

Participants were workers exposed to urothelial carcinogens. Women and current smokers at time of study recruitment were exclusion criteria.

OUTCOMES

Urine cells atypia were ranged into three classes: negative/normal, atypical/suspicious/dysplasia or positive/malignant.

RESULTS

We included 2020 workers over a period of 20 years from 1993 to 2013: 606 worked in rubber manufacturing, 692 from metal processing, 245 in chemical industry and 477 in roadwork and building industry. Workers had a mean exposure of 15.2±10.4 years before their first urine cytology screening. There was a mean of 3.4±4.3 urine cytology screenings per worker between 1993 and 2013. 6478 cytology were normal, 462 suspicious and 13 malignant. Suspicious and malignant cytology occurred in 4.8% of workers exposed for 1-10 years, 6.2% for 11-20 years of exposure, 7.6% for 21-30 years and 8.6% for >30 years (p<0.001). Using exposure for 1-10 years as reference, the adjusted OR of receiving a suspicious or malignant diagnosis increased with duration of exposure: OR=1.50 (95% CI 1.10 to 2.05, p=0.01) for 21-30 years and OR=1.78 (95% CI 1.23 to 2.56, p=0.002) for >30 years of exposure. Using metal processing as reference, the risk of pathological urine cytology results increased for rubber manufacturing (OR=1.32, 95% CI 1.05 to 1.65, p=0.02), with a trend for roadwork and building industry (OR=1.39, 95% CI 0.98 to 1.97, p=0.07) and for chemical industry (OR=1.34, 95% CI 0.94 to 1.93, p=0.11).

CONCLUSIONS

Urine cytology is a useful tool in occupational medicine. We promote new guidelines with an early screening of urothelial cancer by cytology, starting with beginning of exposure.

The rubber manufacturing industry: a case report and review of cutaneous exposure and sequelae

Exposure to chemical carcinogens in rubber manufacturing remains a serious occupational health concern. Workers are exposed to these carcinogens via skin or inhalation. Rubber manufacturing work is associated with a high prevalence of dermatologic diseases such as eczema, allergic contact dermatitis and atopic dermatitis. The role that epidermal exposure plays in the development of malignancies historically associated with the rubber industry is less certain. We present a case relevant to this discussion and review the role of skin exposure in the rubber industry, providing an overview of the cutaneous and systemic manifestations of occupational exposures in modern day rubber workers.

Identification of novel thyroid cancer-related genes and chemicals using shortest path algorithm

Thyroid cancer is a typical endocrine malignancy. In the past three decades, the continued growth of its incidence has made it urgent to design effective treatments to treat this disease. To this end, it is necessary to uncover the mechanism underlying this disease. Identification of thyroid cancer-related genes and chemicals is helpful to understand the mechanism of thyroid cancer. In this study, we generalized some previous methods to discover both disease genes and chemicals. The method was based on shortest path algorithm and applied to discover novel thyroid cancer-related genes and chemicals. The analysis of the final obtained genes and chemicals suggests that some of them are crucial to the formation and development of thyroid cancer. It is indicated that the proposed method is effective for the discovery of novel disease genes and chemicals.

Exposure of hairdressers to ortho- and meta-toluidine in hair dyes

BACKGROUND

Carcinogenic aromatic amines derived from hair dyes have recently received new attention. One of these is ortho (o)-toluidine, which is classified as carcinogenic to humans.

OBJECTIVES

To clarify exposure of hairdressers to potentially carcinogenic aromatic amines, including o-toluidine.

METHODS

We measured eight potentially carcinogenic aromatic amines in the blood of 295 hairdressers, 32 users of hair dyes and 60 controls. The study was restricted to female non-smokers. Lifestyle data were collected for all participants using self-administered questionnaires. Blood samples were taken for analysis of ortho-, meta (m)- and para (p)-toluidine; 2-, 3- and 4-ethylaniline, 2,3- and 3,4-dimethylaniline as haemoglobin adducts. The samples were analysed with gas chromatography-tandem mass spectrometry.

RESULTS

Generally, adduct concentrations were in the range of 0-200 pg/g haemoglobin. A comparison of the adduct concentrations found in hairdressers, consumers and controls showed no statistically significant differences. However, for hairdressers, o- and m-toluidine concentrations increased significantly with the weekly number of hair waving (p=0.020) and permanent hair dyeing treatments (p=0.026), respectively. o-Toluidine and m-Toluidine concentrations also tended (p=0.076 and 0.080, respectively) to increase with the frequency of light-colour permanent hair dye treatments.

CONCLUSIONS

Hairdressers who use light-colour permanent hair dyes, other permanent hair dyes and hair waving treatments seem to be exposed to o- and m-toluidine as indicated by associations with the number of treatments performed. Analyses of hair waving and hair dye products should be performed to identify the possible sources of exposure to o- and m-toluidine.

Coronary artery disease and cancer mortality in a cohort of workers exposed to vinyl chloride, carbon disulfide, rotating shift work, and o-toluidine at a chemical manufacturing plant

BACKGROUND

We updated through 2007 the mortality experience of 1,874 workers employed at a New York State chemical manufacturing plant between 1946 and 2006.

METHODS

Reassessed exposures to vinyl chloride, carbon disulfide, and shift work and categories of o-toluidine exposure were based on year, department and job title. Standardized mortality ratios (SMR) compared mortality to that of the US population. Internal comparisons used directly standardized rate ratios.

RESULTS

Hepatobiliary cancer mortality was elevated among workers ever exposed to vinyl chloride (SMR = 3.80, 95% confidence interval 1.89-6.80); directly standardized rates increased with increasing vinyl chloride exposure duration. No increase in non-Hodgkin lymphoma mortality was observed with vinyl chloride and shift work exposures. Internal comparisons showed increased coronary artery disease mortality among long-term workers exposed to carbon disulfide and shift work for 4 years or more.

CONCLUSIONS

Excess coronary artery disease mortality confirms earlier results; further investigation is needed to understand risk factors.