The Environmental Working Group classifies PP as of low to moderate hazard.[34] PP is dope-dyed, no water is used in its dyeing, in contrast with cotton.[35]
In 2008, researchers in Canada asserted that quaternary ammonium biocides and oleamide were leaking out of certain polypropylene labware, affecting experimental results.[36] As polypropylene is used in a wide number of food containers such as those for yogurt, Health Canada media spokesman Paul Duchesne said the department will be reviewing the findings to determine if steps are needed to protect consumers.[37]