David Swenson of 3M Corporation describes an anomaly where workers encountered a strange “invisible wall” in the area under a fast-moving sheet of electrically charged polypropelene film in a factory. This “invisible wall” was strong enough to prevent humans from passing through. A person near this “wall” was unable to turn, and so had to walk backwards to retreat from it.
This occurred in late summer in South Carolina, in extremely high humidity. Polypropelene (PP) film on 50K ft. rolls 20ft wide was being slit and transferred to multiple smaller spools.