A boat exploded Tuesday while it was being filled with gas at a Greenport marina, throwing two people into the water, police say.

Police say the incident happened just before 4 p.m. at the Safe Harbor Stirling Marina.

Police William Gremler, 61, and Lisa Schoenstein, 43, were on the boat at the time of the explosion. They say Gremler was fueling the 29-foot boat and then started it. That's when it exploded and then sank.

The two were airlifted to Stony Brook Medical Center with undisclosed injuries. 

Authorities plan to return to the marina to try and salvage the vessel.