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 estimates that, compared to average people, workers breathing in these particles could be exposed to far higher quantities of a brominated flame retardant (Environ. Sci. Technol., DOI: 10.1021/es302559v).

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 hypothesized that the heat of the board-cutting process would volatilize 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 13 to 15 times higher than those of the original boards.

Wang explains that, from the particles that a worker would breathe in during an hour of cutting, 13 µg of HBCD would deposit into the alveoli, the tiny air sacs in the lungs. 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.