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 conducted last year by the Centers for Disease Control and Prevention. 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. 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 months after the initial investigation. Workers at the facility were also exposed to mercury in the air. 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. The ACGIH threshold limit value for elemental mercury is 25 µg/m³. The report notes that environmental measurements likely underestimated workers’ exposure to mercury in this investigation because processing was suspended during the site visit and the bay door to the processing area was open during sampling. Investigators also found that the workers wore inadequate personal protective equipment.  For more information, read the full report in the July 13 issue of CDC’s .