There have been some concerns lately about the effect, if any, styrene from polystyrene foam food service products is having on our health. The question is whether residual styrene in a polystyrene foam product is safe.
We need to look at the levels of styrene present and the mode of exposure. The polymerization process of styrene to polystyrene (which is completely safe always leaves trace amounts of styrene in polystyrene foam products. Studies have been conducted to measure the quantity of styrene that leaches into liquids contained in a foam cup, and the results are in the range of 5 – 10 parts per billion, which roughly translates to 2.5 micrograms. The question is whether 2.5 micrograms is worrisome.
Styrene toxicity is typically studied in situations of occupational exposure where the vapors of the volatile liquid are inhaled. Even with high levels of exposure, the results are not always clear. A majority of the studies agrees that styrene poses no occupational risk through inhalation at levels less than 20 parts per million. Over an average work day, this works out at around 100,000 micrograms. When compared with the possibility of 2.5 micrograms ending up in a person’s bloodstream from a coffee cup, it is evident that this minuscule level does not pose a risk.
Styrene also occurs naturally. In some instances, there is more styrene in the coffee a person drinks from a foam cup than from the cup itself! Beer has higher levels than the coffee, and cinnamon is exponentially higher again. From this information, it is quite clear that styrene in polystyrene foam food service products is not a cause for concern.