Slicing Polystyrene Produces Problematic Particles

To insulate homes, construction workers sometimes line walls with polystyrene foam boards. The workers slice the boards using a hot wire, releasing nanosized particles into the air that the workers might inhale. A new study, published in the journal Environmental Science & Technology, estimates that, compared to average people, workers breathing in these particles could be exposed to far higher quantities of a brominated flame retardant. Manufacturers add the flame retardant hexabromocyclododecane (HBCD) to polystyrene boards to meet fire safety codes for new buildings. Studies in animals have found that HBCD causes reproductive and neurological problems. In 2010, the Environmental Protection Agency announced plans to add the compound to its list of chemicals that pose a health or environmental risk. Based on previous work on polymer nanoparticles, Jing Wang of the Swiss Federal Institute of Technology, in Zurich, and Andreas C. Gerecke of the Swiss Federal Laboratories for Materials Science and Technology hypothesised that the heat of the board-cutting process would volatilise HBCD, which could then hitch a ride on released nanoparticles. To determine how much HBCD might be released, they cut dense polystyrene foam in an enclosed space and captured released particles. The researchers then used liquid chromatography, mass spectrometry, and other techniques to measure the amount of HBCD on the particles. They found that the particles had concentrations of HBCD 15 times higher than those of the original boards. The team estimates that if a worker breathed in about two-thirds of the particles released during an hour of cutting, that person would inhale 13 µg of HBCD. On average, a person receives exposure to that much HBCD–through furniture foam, household dust, and food packaging—in about one to three months, says Wang. He thinks thermal cutting presents a new and unexpected exposure route that could have significant consequences for workers’ health.