Characterization and Analysis of Airborne Metal Exposures among Workers Recycling Cellular Phones

Abstract

Electronic scrap contains potentially hazardous metals that may become airborne during the recycling process. Occupational exposures to airborne metals created by cellular phone recycling operations are not well characterized in the scientific literature, leaving risk assessors and policy creators little evidence upon which to base electronic scrap management decisions. A quantitative airborne metal exposure survey was conducted on workers shredding, roasting, milling, and assaying recycled cellular phones. Aluminum, arsenic, beryllium, cadmium, chromium, copper, iron, lead, manganese, nickel, selenium, and zinc were all well below the occupational safety and health administration (OSHA) permissible exposure limits (PEL) for shredding, roasting and alloying operations. Based on their percent exceedance values, airborne silver exposure results for all four operations are expected to be above the OSHA PEL (0.01 mg/m3) greater than five percent of the time. When compared to the more toxicologically relevant exposure limit of 0.1 mg/m3, the percent exceedance values for shredding, roasting, and alloying operations are less than 1.0 percent, although milling remains greater than 5.0 percent. Milling results were above the OSHA PEL for copper and lead more than five percent of the time. Operator tasks required to respond to atypical milling and screening equipment malfunctions significantly influenced their exposures. Shredding, roasting and alloying operations with work practice and ventilation controls, as is described in this study, represent a minimal inhalation hazard regarding silver and no inhalation hazard to the operators for all other metals studied.