BATON ROUGE, La. (AP) — Louisiana’s transportation department will start enforcing a mask requirement Monday for nearly all passengers on the state’s ferries to slow the spread of COVID-19.

The Department of Transportation and Development says the mandate follows the U.S. Centers for Disease Control and Prevention requirement issued last month that called for people to wear face coverings on public transportation.

The CDC order makes refusal to wear a mask a violation of federal law. Passengers remaining in vehicles with the windows raised on Louisiana’s ferries will have an exemption.

All other passengers, including motorcycle riders and people outside cars, will be required to mask up.