Philadelphia, PA – WPVI TV, Michele McCormack -A family in Philadelphia’s Strawberry Mansion neighborhood was hospitalized after carbon monoxide poisoning. Two children and their father are expected to be okay. The mother is critically ill.

It was a frightening scene for Lavelle Robinson Junior. Four of his family members had been rushed to the hospital. Firefighters rushed to ventilate their home and the one next door. Robinson’s father, mother, teenage sister and 7-month-old nephew had all been sickened by the odorless, colorless gas carbon monoxide.

Robinson’s mother suffered the most. She was reportedly slipping in and out of consciousness when medics arrived. Firefighters say she was on the second floor where the concentration of carbon monoxide was greatest.

Firefighters say they see a spike in such calls when the temperatures drop and people turn on their heaters for the first time. But a heater was not the culprit here. Turns out a portable generator is to blame.

The CPSC says that last year 36 people died from carbon monoxide poisoning caused by improper use of a portable generator.