Five of seven workers at a fluorescent light recycling facility in Wisconsin were found to have elevated mercury levels during an investigation of potential environmental contamination at the facility last year.
State and county health officials, in collaboration with Wisconsin Department of Natural Resources, conducted an investigation of mercury exposure of workers and an environmental assessment of the facility, surrounding areas, and worker vehicles.
The investigation report notes that the risk for mercury exposure during the manufacture of fluorescent lights has been known since 1965, but risks for exposure during recycling are not as well documented.
Fluorescent lamps are composed of a phosphor-coated glass tube containing mercury vapor and argon. During the recycling process, lamps are crushed, releasing mercury vapor and mercury-containing dusts.
The workers’ urine mercury levels exceeded ACGIH’s biological exposure index for elemental mercury of 20.0 μg/g creatinine. BEIs are intended to indicate chemical concentrations below which nearly all workers should not experience adverse health effects.
Two workers had tremor, a clinical sign of mercury toxicity when examined by a physician during an occupational health appointment in the months after the initial investigation.
According to investigators, mercury levels varied within the building, with a maximum of 207.4 μg/m3 at floor level on the crushing platform. Mercury vapor concentrations measured at breathing height were lower; a maximum of 99.7 μg/m3 was measured on the processing ramp at breathing height.
Investigators found that the workers wore inadequate personal protective equipment. According to the report, which was published in the July 13 issue of CDC’s Morbidity and Mortality Weekly Report, workers at risk for mercury exposure should wear NIOSH-approved respiratory protection for mercury vapor, nitrile or other suitable gloves to prevent contact exposure, and disposable suits with booties.