It happened around 4 p.m. at a home on the 2000 block of OId Bethlehem Pike in Sellersville.
Officers found 51-year-old Susan Hess dead at the scene.
The woman's 54-year-old husband and her 31-year-old son were rushed to an area hospital.
An initial investigation revealed that the leak may be due to a possible faulty appliance in the home.
Police say Hess' other son went to the home after one of the victims didn't show up to work.
"He was actually able to remove his brother and his mother and his father out of the house, rendered some medical aid," said Chief Paul Dickinson of the Pennridge Regional Police Department.
Neighbor Frances Allem is still reeling from the tragedy.
"It's very hard and it's gonna be really hard on the one son's children. They get every other weekend here cause they love their pop-pop and their grandmom," said Allem.
The Bucks County Coroner's Office will determine the woman's exact cause of death.
The father and son remain hospitalized at this time.
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