DIX HILLS, N.Y. (AP) _ A father and his son were overcome by fumes and died as they worked on a cesspool at their home Sunday. A second son who tried to rescue them also died, authorities said.

It was not immediately clear whether the deaths were caused by drowning or exposure to noxious fumes or some other factor, said Officer Michael Maffucci, a Suffolk County police spokesman.

Gaspare Campo, 57, and his son Anthony, 27, were working in the cesspool's overflow section at their Long Island home when they passed out, police said.

Campo's 16-year-old son, Thomas, went into the house and called 911, then went back to try to help his father and brother, Maffucci said.

Rescue workers from the police and fire departments found the father and both sons submerged in about 6 feet of water. Cardiopulmonary resuscitation failed to revive them.

Police said the cesspool overflow they were working in was made of pre-cast cement with a 2-foot round opening that led to a 6-foot wide, 19-foot deep structure.