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1.  Retrospective Assessment of Exposure to Chemicals for a Microelectronics and Business Machine Manufacturing Facility 
A retrospective exposure assessment was performed for use in a health outcomes study of a facility manufacturing circuit boards, business machines, and other equipment during the years 1969–2002. A matrix was developed identifying chemical use by department-year based on company-provided information. Use of six chemical agents (fiberglass, lead, methylene chloride, methyl chloroform, perchloroethylene, and trichloroethylene) and six chemical classes (acid-base, aromatic hydrocarbons, chlorinated hydrocarbons, other hydrocarbons, chlorofluorocarbons, and metals), and general (including unspecified) chemicals was identified. The matrix also contained an assignment for each department-year categorizing the potential for use of chemicals as negligible, intermittent/incidental, or routine. These department-based exposure matrix data were combined with work history data to provide duration of potential chemical use for workers. Negligible, intermittent/incidental or routine extent-of-chemical-use categories comprised 42.6%, 39.4%, and 17.9%, respectively, of total person-years of employment. Cumulative exposure scores were also developed, representing a relative measure of the cumulative extent of potential exposure to the six chemical agents, six chemical classes, and general (including unspecified) chemicals. Additionally, the study period was divided into manufacturing eras showing trends in chemical use, and showing that process use of trichloroethylene and methylene chloride ended in the mid-1980s and the mid-1990s, respectively. This approach may be useful in other assessments addressing a variety of chemicals, and with data constraints common to retrospective chemical exposure studies.
PMCID: PMC4517462  PMID: 24224613
occupational exposure; circuit board manufacture; substrate production; exposure matrix; exposure score; chlorinated solvents; trichloroethylene; perchloroethylene
2.  Occupational Exposure to Polychlorinated Biphenyls and Risk of Breast Cancer 
Environmental Health Perspectives  2008;117(2):276-282.
Despite the endocrine system activity exhibited by polychlorinated biphenyls (PCBs), recent studies have shown little association between PCB exposure and breast cancer mortality.
To further evaluate the relation between PCB exposure and breast cancer risk, we studied incidence, a more sensitive end point than mortality, in an occupational cohort.
We followed 5,752 women employed for at least 1 year in one of three capacitor manufacturing facilities, identifying cases from questionnaires, cancer registries, and death certificates through 1998. We collected lifestyle and reproductive information via questionnaire from participants or next of kin and used semiquantitative job-exposure matrices for inhalation and dermal exposures combined. We generated standardized incidence ratios (SIRs) and standardized rate ratios and used Cox proportional hazards regression models to evaluate potential confounders and effect modifiers.
Overall, the breast cancer SIR was 0.81 (95% confidence interval, 0.72–0.92; n = 257), and regression modeling showed little effect of employment duration or cumulative exposure. However, for the 362 women of questionnaire-identified races other than white, we observed positive, statistically significant associations with employment duration and cumulative exposure; only smoking, birth cohort, and self- or proxy questionnaire completion had statistically significant explanatory power when added to models with exposure metrics.
We found no overall elevation in breast cancer risk after occupational exposure to PCBs. However, the exposure-related risk elevations seen among nonwhite workers, although of limited interpretability given the small number of cases, warrant further investigation, because the usual reproductive risk factors accounted for little of the increased risk.
PMCID: PMC2649231  PMID: 19270799
breast cancer; incidence; occupational epidemiology; polychlorinated biphenyls

Results 1-2 (2)