The product now commonly called duct tape has largely been displaced in HVAC uses with specialized foil tapes designed for sealing heating and ventilation ducts (sometimes referred to erroneously as "duct tapes").
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[The product now commonly called duct tape's] use in ducts has been prohibited by the state of California and by building codes in many other places.
Research was conducted in 1998 on standard duct tape at Lawrence Berkeley National Laboratory, Environmental Energy Technologies Division, which concluded that under challenging but realistic conditions duct tape becomes brittle, fails, and may even fall off completely.