Student Research: Benjamin Howarth

Electromagnetic Field (EMF) Assessment for Electric Trolley Transit Workers in Seattle, Washington
Faculty Advisor: 


Since the early 1970s, scientists have been studying a possible link between exposure to extremely low frequency (ELF) electro-magnetic fields (EMF) and adverse health effects including leukemia and brain cancer. To assess this link, it is often necessary to quantify a person's estimated lifetime exposure using surrogate measures such as wiring codes and occupational job codes. Currently, there are little data for workers in the transportation industry, including electrified trolley systems. An extremely low frequency (ELF) electromagnetic field (EMF) exposure assessment was conducted at Seattle Metro Trolley facilities to collect personal exposure data for this industry segment.

One hundred and four workers employed in various aspects of operation and maintenance of the trolley system volunteered to wear personal magnetic field dosimeters during a typical work shift. Preliminary research has shown that electrified buses and trolleys have the potential for high exposure to drivers and passengers. The goal of this study was to quantify worker's EMF exposure and to determine if these workers received higher exposure than other occupations not associated with the transportation industry. The data collected were analyzed using non-parametric statistical methods including logistic regression and were used to identify and estimate the size of the highly exposed worker groups for further epidemiological study.