The Federal Highway Administration has awarded Washington State Ferries a $2.3 million grant to lower emissions from ferry engines, ferries announced Monday.

Ferries will use the money to add equipment to existing diesel engines in its fleet to cut down on the amount of lubricant oil they burn. The burned lubricant releases emissions that are unhealthy for humans to breathe.

Senior Budget Manager Al McCoy said emissions cutting kits will be installed as ferries are cycled through for regular engine service. They will eventually be used on all 22 vessels in the fleet.

The grant, awarded from the Highway Administration’s Ferry Boat Discretionary funding program, will not cover the full cost of the equipment and ferries will pursue more federal funding McCoy said.

Washington State Ferries was also recently awarded a $2.1 million federal clean air grant as part of the Puget Sound Regional Council Surface Transportation Program.