If officers cannot confirm the powder as a recognizable, safe substance, the passenger will be asked to check or discard it.
In order to reduce the additional screenings and avoid having to take away passenger belongings, TSA is asking all travelers to check any powder of more than 350 milliliters, or about the size of a 12-ounce soda can.
The measure was prompted by the threat of substances such as fentanyl, pepper spray and improvised explosive devices.
“TSA is communicating with our international partners to ensure last points of departure airports align with Pre-Clearance requirements and our domestic procedures as part of our efforts to raise the global aviation security baseline," TSA spokesperson Mike England said.
The enhanced screening measures come two months after TSA announced that all travelers are required to place any personal electronics larger than a cellphone in bins for the X-ray.