Hamburg, NY, WIVBTV – A Hamburg family is recovering Wednesday morning after being overcome by carbon monoxide.

It happened Tuesday night inside a house on Salem Drive.

Fire officials say they found two people unconcious in the basement, and two other people with less severe symptoms upstairs.

Investigators say the CO level inside was off the chart.

Newton Abbott Fire Co. Chief Paul Uzar said, “…very high level of carbon monoxide. There was a gas pump running. Apparently there was water in the basement, and they were trying to pump the basement out and at some point they moved the pump from outside to inside.”

Two of the victims are being treated in a hyperbaric chamber at Millard Fillmore Gates Hospital in Buffalo.

The other two were taken to South Buffalo Mercy for treatment. Their names and conditions are not being released Wednesday morning.