Catherine E. Simmons

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Fluid sealing devices (gaskets and packing) containing asbestos are manufactured and blended with binders such that the asbestos fibers are locked in a matrix that limits the potential for fiber release. Occasionally, fluid sealing devices fail and need to be replaced or are removed during preventive maintenance activities. This is the first study known to(More)
This study on four pieces of heavy construction equipment was conducted to determine the concentration of airborne asbestos fibers during in-frame maintenance and repair activities, which included aggressive techniques that resulted in visible dust from work involving friction products and gaskets. Despite execution of a carefully planned sampling strategy,(More)
Sanding drywall joint compound is a dusty construction activity. We studied potential factors influencing exposure to respirable and total dust for sanders and bystanders in the area of drywall joint compound finishing in 17 test events within a room-scale isolation chamber. We found the air change rate to be negatively correlated with dust C(twa) both in(More)
Drywall finishing is a dusty construction activity. We describe a mathematical model that predicts the time-weighted average concentration of respirable and total dusts in the personal breathing zone of the sander, and in the area surrounding joint compound sanding activities. The model represents spatial variation in dust concentrations using two-zones,(More)
This study assessed a professional pipefitter/welder performing shielded metal arc welding on carbon steel under field conditions. The resulting breathing zone (near field) and area (far field) welding fume concentration data were applied to the two-zone model for the purpose of determining field-derived personal exposure emission (generation) rates during(More)
The selection and application of mathematical models to work tasks is challenging. Previously, we developed and evaluated a semi-empirical two-zone model that predicts time-weighted average (TWA) concentrations (Ctwa) of dust emitted during the sanding of drywall joint compound. Here, we fit the emission rate and random air speed variables of a mechanistic(More)
OBJECTIVE To investigate whether workplace exposures to recognized lymphohematopoietic carcinogens were possibly related to cancers in six semiconductor-manufacturing workers. METHODS A job-exposure matrix was developed for chemical and physical process agents and anticipated by-products. Potential cumulative occupational exposures of the six cases were(More)
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