Cohort study of workers at a New Zealand agrochemical plant to assess the effect of dioxin exposure on mortality.

Objectives: To describe how the exposure to 2,3,7,8-tetrachlorodibenzo--dioxin (TCDD) influenced mortality in a cohort of workers who were exposed more recently, and at lower levels, than other cohorts of trichlorophenol process workers.

Design: A cohort study.

Setting: An agrochemical plant in New Zealand PARTICIPANTS: 1,599 men and women working between 1 January 1969 and 1 November 1988 at a plant producing the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) with TCDD as a contaminant.

Lymphatic and hematopoietic cancers among benzene-exposed workers.

Objective: High benzene exposure is related to acute nonlymphocytic leukemia. Recently, myelodysplastic syndrome has been observed at low benzene exposure levels.

Methods: We updated a mortality study of workers with benzene exposure examining acute nonlymphocytic leukemia and myelodysplastic syndrome.

Brain Cancer in Workers Employed at a Laboratory Research Facility.

Background: An earlier study of research facility workers found more brain cancer deaths than expected, but no workplace exposures were implicated.

Methods: Adding four additional years of vital-status follow-up, we reassessed the risk of death from brain cancer in the same workforce, including 5,284 workers employed between 1963, when the facility opened, and 2007. We compared the work histories of the brain cancer decedents in relationship to when they died and their ages at death.

Cancer mortality of workers exposed to styrene in the U.S. Reinforced plastics and composite industry.

Background: Epidemiologic studies have reported increased risk of lymphohematopoietic cancers, lung cancer, and pancreatic cancer after exposure to styrene, although findings across studies are not consistent.

Methods: We update a large study of reinforced plastic industry workers with relatively high exposures to styrene, examining cancer risks associated with exposure levels. The study includes 15,826 workers who were exposed between 1948 and 1977 with vital-status follow-up from 1948 to 2008.

Elimination rates of dioxin congeners in former chlorophenol workers from Midland, Michigan.

Background: Exposure reconstructions and risk assessments for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other dioxins rely on estimates of elimination rates. Limited data are available on elimination rates for congeners other than TCDD.

Objectives: We estimated apparent elimination rates using a simple first-order one-compartment model for selected dioxin congeners based on repeated blood sampling in a previously studied population.

Cancer incidence of 2,4-D production workers.

Despite showing no evidence of carcinogenicity in laboratory animals, the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been associated with non-Hodgkin lymphoma (NHL) in some human epidemiology studies, albeit inconsistently. We matched an existing cohort of 2,4-D manufacturing employees with cancer registries in three US states resulting in 244 cancers compared to 276 expected cases. The Standardized Incidence Ratio (SIR) for the 14 NHL cases was 1.

Mortality rates among workers exposed to dioxins in the manufacture of pentachlorophenol.

Objective: We sought to determine if workers exposed to dioxins in pentachlorophenol (PCP) manufacturing were at increased risk of death from specific causes.

Methods: We examined death rates among 773 workers exposed to chlorinated dioxins during PCP manufacturing from 1937 to 1980 using serum dioxin evaluations to estimate exposures to five dioxins.

Results: Deaths from all causes combined, all cancers combined, lung cancer, diabetes, and ischemic heart disease were near expected levels.

Mortality rates among trichlorophenol workers with exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

The authors examined 1,615 workers exposed to dioxins in trichlorophenol production in Midland, Michigan, to determine if there were increased mortality rates from exposure. Historical dioxin levels were estimated by a serum survey of workers. Vital status was followed from 1942 to 2003, and cause-specific death rates and trends with exposure were evaluated.

Serum concentrations of chlorinated dibenzo-p-dioxins and dibenzofurans among former New Zealand trichlorophenol workers.

This study examined serum levels of 2,3,7,8-substituted chlorinated dioxins and furans, and 15 PCBs for 346 New Zealand employees who worked at a site that manufactured 2,4,5-trichlorophenol (TCP) and 2,4,5-trichlorophenoxy acetic acid (2,4,5-T). Participants with potential TCP or 2,4,5-T exposures had mean lipid-adjusted 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) levels of 9.9 ng kg(-1) lipid compared to 4.

TCDD exposure estimation for workers at a New Zealand 2,4,5-T manufacturing facility based on serum sampling data.

Employment in the manufacture of the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) is associated with potential exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and elevated serum lipid TCDD concentrations can be measured in workers for decades after terminated occupational exposure. As part of an epidemiological study of 1599 workers employed at a facility in New Plymouth, New Zealand that manufactured 2,4,5-T, serum TCDD concentrations measured in blood samples from 346 workers were used with work history records and a simple pharmacokinetic model in a linear regression to estimate dose rates associated with specific job exposure groups at the facility. The model was used to estimate serum TCDD concentration profiles over time for each individual in the full study group and accounted for 30% of the observed variance in TCDD concentrations in the serum donor subgroup.

Mortality study update of ethylene oxide workers in chemical manufacturing: a 15 year update.

Objective: To investigate the long-term mortality patterns of workers with past exposure to ethylene oxide (EO).

Methods: We redefined and updated a cohort of male workers employed in industrial facilities where EO was produced or used. All 2063 men were employed between 1940 and the end of 1988 and were observed for mortality through 2003.

Mortality in employees at a New Zealand agrochemical manufacturing site.

Background: Previous studies at the Dow AgroSciences (Formerly Ivon Watkins-Dow) plant in New Plymouth, New Zealand, had raised concerns about the cancer risk in a subset of workers at the site with potential exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin. As the plant had been involved in the synthesis and formulation of a wide range of agrochemicals and their feedstocks, we examined the mortality risk for all workers at the site.

Aims: To quantify the mortality hazards arising from employment at the Dow AgroSciences agrochemical production site in New Plymouth, New Zealand.

Chlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyl profiles of workers with trichlorophenol and pentachlorophenol exposures.

We examined the serum lipid adjusted levels of 2,3,7,8-substituted chlorinated dioxins and furans, and four coplanar PCBs for 98 workers. We found workers who worked only in the trichlorophenol units had mean lipid adjusted 2,3,7,8-TCDD levels of 36.8 ppt significantly higher (p<0.

Mortality among chemical workers at Texas City plant: 1940-2001.

Objectives: To evaluate the mortality experience of workers at a major chemical manufacturing site and to examine brain and liver cancers excesses reported at this site in previous studies.

Methods: This study included 9,730 employees at the Texas City location who worked between 1940 and 2001. Standardized mortality ratios and confidence intervals were calculated.

Factors related to dioxin and furan body levels among Michigan workers.

We evaluated serum concentrations of five selected dioxin, furan, and polychlorinated biphenyls (PCB) congeners among 412 workers at a Midland, Michigan plant that manufactured trichlorophenol and pentachlorophenol (PCP) and formulated chlorophenol-based products. We examined occupational indicators of exposure to these chlorophenols taking into account intrinsic factors such as age and body fat and potential environmental sources of exposure from consumption of local game and fish and other occupations. All five congeners were significantly associated with age and body fat.

Serum concentrations of chlorinated dibenzo-p-dioxins and dibenzofurans among former Michigan trichlorophenol and pentachlorophenol workers.

This study examines serum levels of 2,3,7,8-substituted chlorinated dioxins and furans, and PCBs for 375 Michigan workers with potential chlorophenol exposure, 37 Worker Referents, and 71 Community Referents. The chlorophenol workers were last exposed to trichlorophenol and/or pentachlorophenol 26-62 years ago. Employees working only in the trichlorophenol units had mean lipid-adjusted 2378-tetrachlorodibenzo-p-dioxin (TCDD) levels of 15.

Mortality study update of acrylamide workers.

Objective: The authors examined the long-term health effects of occupational exposure to acrylamide among production and polymerisation workers.

Methods: An earlier study of 371 acrylamide workers was expanded to include employees hired since 1979. In this updated study, 696 acrylamide workers were followed from 1955 through 2001 to ascertain vital status and cause of death.

Body mass index and serum chlorinated dibenzo-p-dioxin and dibenzofuran levels.

Several studies have found that current levels of 2,3,7,8 tetrachlorodibenzo-p-dioxin in serum lipids are related to age with older persons generally having higher levels. To account for this age pattern, reference ranges based on national samples have been established in order to allow determination of background levels for regional studies. In several studies, body mass index (BMI), has also been associated with current 2,3,7,8 tetrachlorodibenzo-p-dioxin levels with increasing body mass index related to increasing levels.

Communication of epidemiology study results by industry: the Dow Chemical Company approach.

Communicating epidemiology study results to subjects, affected workers, and community members is an important part of compliance and alignment with our company's policies, industry's Responsible Care Principles, and the doctrines of Good Epidemiology Practices. It is the responsibility of the investigators to interpret their research appropriately for each audience, and to assure that all who have a need or right to know get information in a form meaningful to them. We discuss study communication with examples from a recent evaluation of communication efforts within Dow and our experience with occupational and community studies on dioxin.