Vanegas-Fuentes then lost his footing and fell through the three-foot-wide opening.
Officials say the pool is approximately 16-feet deep and was half-full at the time. High levels of methane gas often collect within septic tanks, police said.
Suarez ran into the house to call 911, and Calderon-Castro jumped into the cesspool after his now unconscious friend. He held onto a hose Suarez had thrown down but was also quickly overcome by fumes.
Firefighters pulled the teens to safety using hooked poles and rushed them to the hospital.
Last year, a 17-year-old died after falling into a cesspool at a Smithtown Dunkin’ Donuts. And in 2007, a Long Island landscaper died after driving a lawn mower into a cesspool in Deer Park.