Rubber Industry Workers Research Articles

Environmentally safe preservation and stabilization of natural rubber latex in an acidic environment

AbstractNatural rubber is an indispensable raw material that supplies about half of the world's rubber consumption. The latex that is extracted from the trees is composed of polyisoprene rubber, proteins, sugars, amino acids, lipids, and minerals. When the liquid latex emanates from the trees, it comes into contact with bacteria that cause it to decompose and coagulate. To hinder the decomposition and destabilization process, ammonia and other environmental and health hazard chemicals are added to the latex. The addition of these chemicals affects the health of plantation and rubber industry workers and results in residues that are contaminated with these chemicals, which require that processing facility effluents undergo costly treatment processes. Here, we present two novel liquid latex preservation and stabilization methods in an acid medium free of ammonia or other dangerous chemicals. The first method uses dodecyl benzene sulfonic acid to both stabilise and preserve the liquid latex, and the second uses ethoxylated tridecyl alcohol to stabilise and hydrofluoric acid to preserve the colloidal suspension. Both formulations result in rubber with superior mechanical properties, that is safe for the rubber plantation and industry workers, and with residues that no longer adversely affect the environment.

DNA Damage on Buccal Epithelial Cells, Personal Working in the Rubber Industry Occupationally Exposed to Carbon Disulfide (CS2).

The most significant industrial utilization of carbon disulfide (CS2) has been in the manufacture of cellulose rayon, cellophane, and rubber industry. CS2 prompts expanded recurrence of chromosomal variations in laborers occupationally exposed to CS2. In the current study, the DNA analysis was carried out from exfoliated buccal epithelial cells from rubber industry workers exposed to CS2 and an equal number of healthy control subjects. Both the control and experimental subjects were categorized by their smoking habits such as smokers (S) and non-smokers (NS). Furthermore, experimental subjects were further separated based on their exposure period. Students t-test statistical tools were used to analyze the final results. The present analysis identified a high frequency of DNA damage in rubber industry workers (16.55±0.43) than control subjects (9.8±0.21). Also, maximum number of DNA damage detected in smoking experimental group (18.27±0.02) than non-smoking experimental (15.02±0.01) and smoking control groups (10.25±0.04 ). Smoking habits synergistically increased the DNA damage in the rubber industry workers exposed to CS2.

Estimated number of cancers attributable to occupational exposures in France in 2017: an update using a new method for improved estimates.

Over the last 50 years, occupational exposure to carcinogenic agents has been widely regulated in France. Report population-attributable fraction (PAF) and number of attributable cancer cases linked to occupational exposure in France based on an updated method to estimate lifetime occupational exposure prevalence. Population-level prevalence of lifetime exposure to ten carcinogenic agents (asbestos, benzene, chromium VI, diesel engine exhaust, formaldehyde, nickel compounds, polycyclic aromatic hydrocarbons, silica dust, trichloroethylene, wood dust) and two occupational circumstances (painters and rubber industry workers) were estimated using the French Census linked with MATGÉNÉ job-exposure matrices and French occupational surveys. PAF and number of attributable cancer cases were calculated using the estimated prevalence, relative risks from systematic review and national estimates of cancer incidence in 2017. The lifetime occupational exposure prevalences were much higher in men than in women ranging from 0.2% (workers in the rubber industry) to 10.2% in men (silica), and from 0.10% (benzene, PAH and workers in the rubber industry) to 5.7% in women (formaldehyde). In total, 4,818 cancer cases (men: 4,223; women: 595) were attributable to the ten studied carcinogens and two occupational circumstances, representing 5.2% of cases among the studied cancer sites (M: 7.0%; W: 1.9%). In both sexes, mesothelioma (M: 689 cases; W: 160) and lung cancer (M: 3,032; W: 308) were the largest cancer sites impacted by the studied occupational agents and circumstances. A moderate proportion of the cancer cases in France is linked to carcinogens in occupational settings. Our method provides more precise estimates of attributable cancer taking into account evolution of exposure to occupational agents by sex, age and time. This methodology can be easily replicated using cross-sectional occupational data to aid priority making and implementation of prevention strategies in the workplace.

An innovative method to estimate lifetime prevalence of carcinogenic occupational circumstances: the example of painters and workers of the rubber manufacturing industry in France.

Existing methods to estimate lifetime exposure to occupational carcinogenic agents could be improved. We propose a new method to estimate the lifetime prevalence of exposure to occupational carcinogens using the example of painters and workers of the rubber industry in France. From census, we calculated the proportion of painters and rubber industry workers using predefined occupational codes related to each occupation by sex and 10-year age group in 1982, 1990, 1999, 2007, and 2013. Using a beta-regression model, we obtained the yearly prevalence of exposure by 10-year age group over the period 1967-2007. We estimated the age- and sex-specific lifetime prevalence of exposure of the population in 2017 over 1967-2007, summing up the estimated prevalence of exposure for years 1967, 1977, 1987, 1997, and 2007 combined with a sex- and age-specific turnover factor. Corresponding population-attributable fractions were estimated for lung and bladder cancers in 2017. In 2017, we estimated that 5.6 and 0.2% of men in France had ever worked as a painter or in the rubber industry, respectively, during their working time. The lifetime prevalence of ever having worked as a painter or in the rubber industry was much lower in women: 1.8% and 0.1%, respectively. We estimated that 950 lung cancer and 40 bladder cancer cases were attributable to these occupations in 2017. Based on accurate data and taking into account evolution of specific jobs over time, the proposed method provides good estimates of lifetime prevalence of exposure to occupational carcinogens. It could be applied in any other country with similar data.

N-Nitrosodimethylamine. Documentation of proposed values of occupational exposure limits (OELs)

N-Nitrosodimethylamine. Documentation of proposed values of occupational exposure limits (OELs)

Meta-analysis of occupational exposures in the rubber manufacturing industry and risk of cancer.

Occupational exposures in the rubber manufacturing industry showed an increased risk of cancer and have been classified as a group 1 carcinogen, largely from studies on workers employed before 1950s. Cancer sites considered as causally associated are bladder, lung and stomach, and leukaemia. Recent studies did not report an increased risk of cancer. A meta-analysis was conducted on observational studies published until April 2016 on occupational exposures in the rubber manufacturing industry and risk of cancer. Case-control and cohort studies were included. Random effect models were used. Heterogeneity and publication bias were evaluated. Stratified analyses were conducted on study characteristics. The literature search identified 46 cohorts and 59 case-control studies. An increased risk was found for bladder cancer [standardised incidence ratio (SRR) = 1.36; 95% confidence interval (CI) 1.18, 1.57], leukaemia (SRR = 1.29; 95% CI 1.11, 1.52), lymphatic and haematopoietic system (SRR = 1.16; 95% CI 1.02, 1.31) and larynx cancer (SRR = 1.46; 95% CI 1.10, 1.94). For lung cancer, a borderline statistically significant increased risk was identified (SRR = 1.08; 95% CI 0.99, 1.17). No association was found for stomach cancer (SRR = 1.06; 95% CI 0.95, 1.17). In stratified analyses, risks of cancer were not increased for workers employed after 1960 for bladder cancer (SRR = 1.06; 95% CI 0.66, 1.71), lung cancer (SRR = 0.94; 95% CI 0.68, 1.29) or leukaemia (SRR = 0.92; 95% CI 0.62, 1.36). Risk of bladder cancer, lung cancer, leukaemia and larynx cancer were increased among workers in rubber industry. Evidence of elevated risks was no longer seen for bladder cancer, lung cancer or leukemia among workers first employed after 1960.

Dermal thiram exposure of workers in rubber industry

A non-catenated nickel (II) pillared paddlewheel metal-organic framework is synthesized through a combination of solvent-assisted linker exchange and transmetallation. Compared to its isostructural Zn(II) analogue, the nickel (II) pillared paddlewheel metal-organic framework features an enhanced N2 sorption performance. It is notable that the nickel (II)-based metal-organic framework could not (in our hands) be synthesized de novo. The experimental results validate that multiple building-block-replacement (BBR) methods can be utilized to access materials that are challenging to synthesize directly.

Evaluación ergonómica del procesamiento del caucho natural en plantaciones y pequeñas empresas

This exploratory study used OWAS (Ovako Working Posture Analysing System) to analyze the working postures of natural rubber tappers and rubber industry workers. A community of natural rubber farmers of Taraza and five small companies of Medellin and Itagui, all of them allocated in Antioquia-Colombia, participated in this study. Processes were analyzed in-situ and videotapes of activities were recorded for carrying out a movement study. For an overall distribution of trunk postures, OWAS identified that a bent and twisted trunk posture which fell into action category 4, was the major poor posture for rubber tappers and rubber industry workers. This study also identified that latex tapping, latex collection, mixing in two roll mills and metallic molds operation were the four activities in which the major working posture risks were observed. It was found that reduction of posture risks in natural rubber production chain requires designing and implementing plans considering organizational culture, socio-economic and sociodemographic factors of natural rubber farmers and small rubber manufacturing industries, besides the use of some useful tools that reduce the handling of heavy loads.

1,3-Butadiene, styrene and lymphohematopoietic cancer among male synthetic rubber industry workers – Preliminary exposure-response analyses

We updated the mortality experience of North American synthetic rubber industry workers to include follow-up from 1944 through 2009, adding 11 years of mortality data to previous investigations. The present analysis used Cox regression to examine the exposure-response relationship between 1,3-butadiene (BD) and styrene (STY) parts per million (ppm)-years and leukemia (N = 114 deaths), non-Hodgkin lymphoma (NHL) (N = 89) and multiple myeloma (MM) (N = 48). A pattern of largely monotonically increasing rate ratios across deciles of BD ppm-years and a positive, statistically significant exposure-response trend were observed for BD ppm-years and leukemia. Using continuous, untransformed BD ppm-years the regression coefficient (β) adjusted only for age was 2.6 × 10−4 (p < 0.01); the regression coefficient adjusted for age, year of birth, race and plant was 2.9 × 10−4 (p < 0.01). STY ppm-years also displayed a positive exposure-response association with leukemia. STY and BD were strongly correlated, and the separate effects of these two agents could not be estimated. For NHL, a pattern of approximately monotonically increasing rate ratios across deciles of exposure was seen for STY but not for BD; the test of trend was statistically significant in one of five models that used different STY exposure metrics and adjusted for age and other covariates. BD ppm-years and STY ppm-years were not associated with MM. The present analyses indicated a positive exposure-response relationship between BD cumulative exposure and leukemia. This result along with other research and biological information support an interpretation that BD causes leukemia in humans. STY exposure also was positively associated with leukemia, but its independent effect could not be delineated because of its strong correlation with BD, and there is no external support for a STY-leukemia association. STY, but not BD, was associated positively with NHL. The interpretation of this result is uncertain because the exposure-response data were statistically imprecise and because consistent support for causality from other studies is lacking. The current study provides no support for an association between BD or STY and MM.

A comprehensive review of occupational and general population cancer risk: 1,3-Butadiene exposure–response modeling for all leukemia, acute myelogenous leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, myeloid neoplasm and lymphoid neoplasm

Excess cancer risks associated with 1,3-butadiene (BD) inhalation exposures are calculated using an extensive data set developed by the University of Alabama at Birmingham (UAB) from an epidemiology study of North American workers in the styrene butadiene rubber (SBR) industry. While the UAB study followed SBR workers, risk calculations can be adapted to estimate both occupational and general population risks.The data from the UAB SBR study offer an opportunity to quantitatively evaluate the association between cumulative exposure to BD and different types of cancer, accounting for the number of tasks involving high-intensity exposures to BD as well as confounding associated with the exposures to the multiple other chemicals in the SBR industry. Quantitative associations of BD exposure and cancer, specifically leukemia, can be further characterized by leukemia type, including potential associations with acute myelogenous leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myelogenous leukemia (CML), and the groups of lymphoid and myeloid neoplasms. Collectively, these multiple evaluations lead to a comprehensive analysis that makes use of all of the available information and is consistent with the risk assessment goals of the USEPA and other regulatory agencies, and in line with the recommendations of the USEPA Science Advisory Board. While a range of cancer risk values can result from these multiple factors, a preferred case for occupational and general population risk is highlighted.Cox proportional hazards models are used to fit exposure–response models to the most recent UAB data. The slope of the model with cumulative BD ppm-years as the predictor variable is not statistically significantly greater than zero for CML, AML, or, when any one of eight exposure covariates is added to the model, for all leukemias combined. The slope for CLL is statistically significantly different from zero. The slope for myeloid neoplasms is not statistically significantly greater than zero while the slope for lymphoid neoplasms is statistically significantly greater than zero.The excess risk for the general population is largest for lymphoid neoplasms. The best estimates of the environmental concentrations (ECs) associated with an excess risk of 1/100,000 by age 70years for lymphoid neoplasms, all leukemias, and CLL are EC(1/100,000)’s equal to 0.06, 0.16 and 0.38ppm, respectively. The best estimates of the occupational BD exposure from 20 to 65years of age associated with an excess risk of 1/10,000 by age 70years for lymphoid neoplasms, all leukemias, and CLL are the EC(1/10,000)’s of 2.7, 7.3 and 15.1ppm, respectively.

A Survey on Chemical Hazards and Liver Function in Rubber Industry Workers in Iran

Rubber industries workers are at risk of hepatic dysfunction from exposure to rubber dust and a mixture of different hydrocarbons. This study aimed to evaluate the relation between chemical hazards in workplace and serum hepatic transaminases in rubber industry workers in Iran. This historical cohort study was conducted in a rubber-manufacturing industry in Mashhad. It con-sisted of 91 workers with chemical substances exposure and 85 workers not exposed to chemicals. Hepatic transaminases including alanine transaminase (ALT) and aspartate transaminase (AST) were compared between these two groups. Required data were collected through questionnaire, liver enzymes evaluation, and environmental monitoring of chemical substances. The data were analyzed with SPSS 11.5. A total of 176 workers enrolled in this study included 113 (64.2%) male and 73 (35.8%) female. The mean of age and employment duration in exposed group were 29.22 ± 3.99 and 5.41 ± 2.77 and in non-exposed group were 30.33 ± 4.11 and 5.29 ± 2.77 respectively. The mean of ALT in exposed and non-exposed groups was 31.3 ± 8.04 and 23.8 ± 10.42 (p = 0.01) and the mean of AST was 29.6 ± 9.7 and 27.3 ± 8.2 (p = 0.1) respectively. A significant difference was shown between mean of ALT at the date of employment and at the time of the study in exposed group. According to our findings evaluation of serum transaminases is a useful screening method which might be beneficial in early detection of hepatocellular injuries in rubber industry workers.

Factors Affecting Free Labor Movement Amongst Rubber Industry Workers Within the ASEAN Economic Community-AEC

Factors Affecting Free Labor Movement Amongst Rubber Industry Workers Within the ASEAN Economic Community-AEC

Biochemical markers of industrial pollutants action on the rubber industry workers

Aim. To assess the health status of employees contacting with industrial pollutants by examining the processes of free-radical and microsomal oxidation, antioxidant protection, energy metabolism and electrolyte metabolism. Methods. Biochemical parameters of blood, saliva and urine samples of 115 employees of OJSC «Ufa plant of elastomer materials, articles and structures» and 110 employees of JSC «Kauchuk» from the various workshops were examined. Considering the particularities of industrial factors, their action on the employees’ health, ways of absorption at airways, oral cavity and hand skin, two groups (A and B) were formed. Group A included employees contacting with aromatic hydrocarbons (JSC «Kauchuk»). Group B included employees contacting with chlorinated hydrocarbons (OJSC «Ufa plant of elastomer materials, articles and structures»). Control group included administrative clerk workers without influence of industrial factors. Results. Free radical peroxidation reaction with the registration of body fluids chemiluminescence was the most informative biochemical marker of (1,2-dichloroethane, methylene chloride, trichlorethylene, carbon tetrachloride) and aromatic (benzene, 1,2,4,5-tetramethyl benzene, toluene), hydrocarbons action on employees. Сonclusion. Examination of free radical and microsomal peroxidation, antioxidant system, energy metabolism and electrolyte metabolism is a useful prognostic tool for a quantitative assessment of the oxidative processes activity for identification of high-risk groups at picking up the staff for the work related to chemical exposure as well as for the individual prevention and oxidative processes medical correction planning.

Extended Cancer Mortality Follow-Up of a German Rubber Industry Cohort

We extended follow-up of a cohort of German rubber industry workers (active or retired in 1981) by 9 years (1992 to 2000) to reassess previously observed cancer mortality risks. We calculated standardized mortality ratios and stratified results by work area, duration of employment, and year of hire. The cohort includes 11,632 men and 1863 women from five tire or general rubber goods producing factories. Among men we observed significantly elevated standardized mortality ratios for cancers of the lung and the pleura in the full cohort and in specific strata. Among women we observed a significantly elevated standardized mortality ratio for cancer of the lung. We observed excess risk for several cancer sites among men and women. Further cancer risk analysis of workers in the rubber industry should focus on differences in work areas and associated exposures.

Combined Effect of Cigarette Smoking and Occupational Exposures on Lung Function: A Cross-sectional Study of Rubber Industry Workers

Combined Effect of Cigarette Smoking and Occupational Exposures on Lung Function: A Cross-sectional Study of Rubber Industry Workers

Quantitative risk assessment of exposures to butadiene in EU occupational settings based on the University of Alabama at Birmingham epidemiological study

The excess risks due to 1,3-butadiene (BD) inhalation in EU occupational settings are quantified for leukemia, AML, CLL, CML, lymphoid neoplasms, and myeloid neoplasms. The most recent data from the University of Alabama at Birmingham epidemiological study of North American workers in the styrene-butadiene rubber industry are modeled.The number of high-intensity tasks (HITs) and other exposure covariates may be more important predictors than cumulative BD ppm-years alone. For example, all of the 71 leukemia decedents in the UAB study who were exposed to BD had some BD HITs. None of the 1192 exposed workers without BD HITs had leukemia mortalities.The authors’ best estimate (consolidated over all endpoints) of the average occupational BD exposure concentration for 45years of exposure starting at age 20 corresponding to an added risk of 1/10,000 by age 70 is 7.2ppm.Cumulative BD ppm-years is not statistically significantly associated with CML, AML, or myeloid neoplasms or (after any one of eight exposure covariates is included in the modeling) leukemia. The statistical significance of the slopes for leukemia, CLL, and lymphoid neoplasms unadjusted for covariate effects disappears when modeling is restricted to person years with less than 200 cumulative BD ppm-years.

Perioperative Latex Allergy

The prevalence of latex allergy varies greatly depending on the population studied and the methods used to detect sensitization. Subjects considered to be at high risk for latex allergy are rubber industry workers, children with spina bifida and urological abnormalities, children undergoing multiple surgical procedures and with urinary catheterization, health care workers and people with food allergy (latex fruit syndrome). In this paper we report a review of latex proteins, the symptoms of latex allergy, diagnosis and management in subjects with latex allergy.

LATEX ALLERGY—ILLUSTRATIVE CASE REPORT

Natural latex from rubber-tree is allergenic with significant cumulative latex exposure, as seen in healthcare providers and workers in rubber industry and also patients who had undergone surgeries early in life1. Symptoms of latex allergy may progress rapidly and unpredictably to anaphylaxis. Diagnosis is usually made initially by history. A case report of atypical contact dermatitis type of latex allergy is described in this case report.

1,3-Butadiene, Styrene and Lung Cancer Among Synthetic Rubber Industry Workers

To evaluate the association between cumulative exposure to 1,3-butadiene (BD) or styrene (STY) and lung cancer among synthetic rubber industry workers. Internal Cox regression analyses were performed both with and without natural logarithm transformation of exposure variables and both with and without the inclusion of those unexposed to monomers. Among women, analyses using untransformed BD exposure showed no trend. Analyses using natural logarithm-transformed BD exposure indicated a positive trend when the unexposed were included (P < 0.05) and an inverse trend when the unexposed were excluded (P < 0.05). No exposure-response trends were seen for BD among men or for STY among women or men. These results suggest that the association between BD and lung cancer, seen in some analyses of female employees, is not causal. STY did not appear to be associated with lung cancer.

The effect of uncertainty in exposure estimation on the exposure-response relation between 1,3-butadiene and leukemia.

In a follow-up study of mortality among North American synthetic rubber industry workers, cumulative exposure to 1,3-butadiene was positively associated with leukemia. Problems with historical exposure estimation, however, may have distorted the association. To evaluate the impact of potential inaccuracies in exposure estimation, we conducted uncertainty analyses of the relation between cumulative exposure to butadiene and leukemia. We created the 1,000 sets of butadiene estimates using job-exposure matrices consisting of exposure values that corresponded to randomly selected percentiles of the approximate probability distribution of plant-, work area/job group-, and year specific butadiene ppm. We then analyzed the relation between cumulative exposure to butadiene and leukemia for each of the 1,000 sets of butadiene estimates. In the uncertainty analysis, the point estimate of the RR for the first non zero exposure category (>0–<37.5 ppm-years) was most likely to be about 1.5. The rate ratio for the second exposure category (37.5–<184.7 ppm-years) was most likely to range from 1.5 to 1.8. The RR for category 3 of exposure (184.7–<425.0 ppm-years) was most likely between 2.1 and 3.0. The RR for the highest exposure category (425.0+ ppm-years) was likely to be between 2.9 and 3.7. This range off RR point estimates can best be interpreted as a probability distribution that describes our uncertainty in RR point estimates due to uncertainty in exposure estimation. After considering the complete probability distributions of butadiene exposure estimates, the exposure-response association of butadiene and leukemia was maintained. This exercise was a unique example of how uncertainty analyses can be used to investigate and support an observed measure of effect when occupational exposure estimates are employed in the absence of direct exposure measurements.