LI firefighters in arson bust

Three volunteer firefighters on Long Island moonlighted as arsonists — secretly setting blazes in abandoned buildings just so they could later rush to the scene and put them out like heroes, sources and officials said.

“These guys were new guys. They just wanted to put fires out, these a--holes,” said a law-enforcement source. “They put people’s lives in danger responding to that s--t.”

Austin Lehman, 19, and Stephen Hernandez, 27, allegedly used gasoline to set blazes in five empty houses in Central Islip and Hauppauge between last October and January, Suffolk County Police Acting Commissioner Stuart Cameron said.

A third volunteer at the Central Islip Fire Department, Shawn Key, 27, helped them with one of the fires, officials said.

All three were hit Tuesday with charges of arson and arraigned.

Cameron wouldn’t comment on a motive but said the men “responded to the fires they set.”

He noted it was lucky no one was hurt by the firebugs. “There was a great potential for injuries with all these fires — both to civilians and to members of the volunteer fire service,” he said.

The suspects were all relatively new volunteers, Cameron added.

A source said all three had taken the FDNY and EMS tests and hoped to be hired by the city.

A Facebook page belonging to Lehman says the teenager signed up to volunteer with the department last May.