The Transportation Security Administration plans to add another item to the gels, liquids and laptops requiring additional scrutiny for US-bound airline passengers -- powders.

Passengers carrying more than twelve ounces of powder -- the size of a regular soda can -- will be subject to additional screening starting on June 30, TSA spokesman Michael England said. Such items include certain cosmetics, spices and powdered drink mixes.

The policy was enacted partly in response to a foiled bomb plot on an Etihad Airways plane flying to Abu Dhabi from Sydney in July, England said. He added that "improvised devices containing powder explosives have always been a concern of TSA's."

In order to avoid authorities disposing of the powder-like substances, England recommended that passengers place any powder products inside their checked baggage. Powders in carry-on bags will be discarded if screening procedures are unable to effectively resolve them.

The policy shouldn't affect domestic passengers, England said, as TSA has been screening powders, foods and other materials that can obstruct clear images on X-ray machines on domestic flights for about a year.

The heightened security measures follow a series of air-travel regulations implemented in the last two years. In March 2017, the Department of Homeland Security enforced an electronics ban, including laptops, on flights arriving into the US from 10 major airports in the Middle East. The "laptop ban" was later lifted after other security measures were put in place.