Spring Valley, NY- SPRING VALLEY — With an autumn chill in the air Monday night, Lori Graham turned on the heat inside her Spring Valley apartment where she lived with her three children.

Graham soon started feeling weak, nauseous, and her head started pounding. She slowly was being poisoned by carbon monoxide, she later learned.

“My kids had fallen asleep,” Graham said. “I was getting nauseous and falling. I heard my daughter trying to call me. I couldn’t move. My daughter passed out.”

Then Graham was startled by a banging on her apartment door at 67 S. Main St. It was the Spring Valley Fire Department.

“The firemen started storming through and they told us we have to leave,” she said. “We had to be evacuated.”

Graham’s downstairs neighbors had called Spring Valley police after their carbon monoxide alarm had gone off about 9:45 p.m. Graham, who already was planning to move to another apartment this coming weekend, said her detectors did not go off.

Graham and her three young children, along with the two adults and four children who lived downstairs were taken to either Good Samaritan or Nyack hospitals for treatment. They were given oxygen and tests found no lingering effects.

An estimated 2,100 people die annually in the United States from unintentional carbon monoxide poisoning and thousands more are poisoned and needed medical attention, according to the Journal of the American Medical Association. The medical journal also says more than 10,000 people yearly survive carbon monoxide poisoning.

Carbon monoxide is considered a silent killer. The gas is colorless and odorless and can be produced by burning any fuel, such as natural gas, gasoline, wood or coal. Carbon monoxide can come from household appliances such as stoves or washers and dryers. A county law requiring carbon monoxide detectors in homes and apartments went into effect earlier in the summer.

Last week on Staten Island, a 7-year-old girl, her mother, 36, and her grandmother, 60, were found dead in their home of apparent carbon monoxide poisoning.

The levels of carbon monoxide filtering through 67 S. Main St. on Monday night had reached potentially lethal levels.

Spring Valley Fire Chief Fred Thibault said their carbon monoxide detecting instruments indicated 55 units of carbon monoxide in the building. He said the norm is 5 units. Firefighters opened windows to air out both apartments.

Orange & Rockland Utilities Inc. workers, who were later called to the house about 10:30 p.m., also found carbon monoxide levels above the acceptable levels, spokesman Michael Donovan said. The utility turned off the gas.

Thibault said the 10 people living in the house were lucky the detectors went off in the downstairs apartment, alerting the family living there.

“I am surprised they didn’t pass out,” Thibault said. “I am not a doctor, but the levels of gas inside the house were not good for anyone’s health.”

The families could not return to their homes on Monday night, staying with family members.

On Tuesday, O&R went back to the house to test the appliances and gas connections. The highest levels came from the kitchen stove in the first-floor apartment. Donovan said workers couldn’t say with certainty that the stove caused the problem.

“We went through the place with a fine-toothed comb,” Donovan said. “The readings were normal everywhere in the house with the exception of the first-floor stove. We shut it off and notified the landlord.”

The landlord replaced the stove on Tuesday, Spring Valley Building Inspector Joseph Jacaruso said. No violation notices were issued because the landlords acted immediately, he said.

Jacaruso, who also is a volunteer firefighter, said he had responded to homes with high levels of carbon monoxide levels and had gotten sick.

“You don’t feel it until you almost pass out,” Jacaruso said. “It can come from broken appliances, chimney problems, gas pipes. You never know. You have to be very careful and install carbon monoxide monitors.”