First it targeted manspreading. Now hoverboards.

In a new ad campaign, the Metropolitan Transportation Authority will remind subway and bus riders to leave their hoverboards at home. The popular two-wheeled motorized devices are banned across the system, officials announced on Wednesday.

That means not only no zooming along subway platforms on hoverboards, but also no bringing them into stations or onto trains and buses, either.

“There have been reports of exploding batteries, and certainly you don’t want anything like that in a crowded subway car or a train,” Fernando Ferrer, the vice chairman of the authority’s board, told reporters after a board meeting on Wednesday.

The proliferation of hoverboards has raised safety concerns over injuries among riders and reports of batteries catching fire. More than a few celebrities have embraced them, even as federal officials have warned consumers about the risks and some airlines have banned them.