WINDHAM – A father and his 16-year-old son died from carbon monoxide poisoning after being overcome by the deadly fumes that came from a portable generator in the basement of their home, officials said Friday.

Stewart Townsend, 35, was dead when a friend checked on him at 10:40 a.m. Friday, and his son Nicholas died several hours later at Maine Medical Center in Portland, said Paul Cox, a patrol officer from the Windham Police Department.

The gas-powered generator was used to run the lights and to provide heat, Cox said. The home’s electricity was cut off by Central Maine Power last summer, a spokesman said.

Firefighters arrived to find carbon monoxide levels of greater than 900 parts per million, high enough to render a person unconscious within minutes, Cox said.

While there’s no agreed-upon indoor standard for safe levels of carbon monoxide, the U.S. Environmental Protection Agency recommends that people’s outdoors exposure to the odorless gas be limited to eight hours at 9 parts per million.

A family friend, Scott Benoit, discovered the body of Stewart Townsend on the first floor of the home and performed CPR on the teenager, who was in bed upstairs, Cox said. Benoit, along with a paramedic, were taken to a hospital for observation.

The deaths were the third and fourth in Maine in just over a month attributed to carbon monoxide poisoning from a portable generator.