Buffalo, NY- It’s every parent’s worst nightmare.

Ken Hansen’s daughter, Amanda, went to spend the night at her friend’s house.

The next morning, the 16-year-old West Seneca West High School junior was dead — from carbon monoxide poisoning that had seeped from a malfunctioning basement boiler.

To try to prevent such a tragedy from ever happening to another family, Hansen began pressing for a new law that would require contractors to install a carbon monoxide detector any time they put in a new furnace or water heater.

As the State Senate on Thursday passed a stack of bills that had piled up while it was caught up in a chaotic coup attempt, lawmakers approved “Amanda’s Law.” It is expected to be signed soon by Gov. David A. Paterson and take effect early next year.

“We’re just really excited about it,” Hansen told The Buffalo News on Saturday.

Hansen was out snow blowing in front of his West Seneca home early on the morning of Jan. 17, when his wife yelled to him that their daughter, who was at a friend’s house where she spent the night, was sick.

The Hansens drove over to the friend’s home and saw paramedics performing CPR on their daughter in the back of an ambulance.

“We kind of knew at that point,” Hansen recalled.

Amanda and her friend had spent the night on blankets and pillows spread out next to a boiler closet in the basement. When one of the friend’s parents came downstairs in the morning to check on them, the girls were unresponsive.

Amanda and the friend were rushed to Mercy Hospital, where doctors made repeated attempts to revive Amanda, but could not.

“They called us in,” Hansen said. “They asked us if you guys would like to say goodbye to her.”

The friend survived.

The Hansens were devastated by the death of their only child. “It’s something you never think of: carbon monoxide,” Ken Hansen said of the silent killer. “You worry about your kids with driving and stuff like that.”

Symptoms of carbon monoxide poisoning are often difficult to identify. Victims often feel dizzy, lethargic and sometimes nauseous. They often drift off to sleep as they succumb to the gas. The gas does not have any smell, making it especially hard to detect.

He remembered his daughter as “a girl full of energy,” Ken Hansen said.

“She had more friends than I ever imagined,” he said. “She loved animals. She enjoyed everything. She was never mad.”

Amanda was on the honor roll at her school and was on the varsity swim team at West Seneca West. She adored her job selling ice cream at Route 16 where she would concoct her own delicious flavor combinations, her father recalled.

Two days after her death, the girl’s father decided he had to take action.

“It was something I had to do,” he said. “There are two roads you can take, I just chose the high road.”

He talked to local politicians who put him in touch with Assemblyman Mark J. F. Schroeder, who began crafting legislation to require carbon monoxide detectors.

Hansen commended Schroeder’s commitment to getting Amanda’s Law passed.

“His office has been nonstop with it,” Hansen said.

The Assembly passed its version of the bill June 18. But it was in limbo as to what would happen to the bill in the Senate, which was embroiled in month long chaos.

Hansen, in fact, had been scheduled to address senators in Albany in June, but Schroeder called him the night before to tell him it was off because of the coup.

“That was a little frustrating,” Hansen said.

But late Thursday night, Schroeder called him with the good news: The Senate had taken up Amanda’s Law and passed it.

Now, Hansen’s goal is to continue spreading the word.

His family started a scholarship fund in memory of their daughter. They raised $40,000 at a benefit in March. Awards will be given out annually to a West Seneca West swimmer.

They’ve also appeared in local commercials with Roy’s Plumbing to teach people about the dangers of carbon monoxide poisoning.

In addition to Amanda’s Law, the State Legislature has designated January as carbon monoxide awareness month.

Hansen is also working with West Seneca fire chiefs to give talks at local schools about the poisoning danger.

And he now plans to take the campaign nationwide.

“There are only three or four states that have any carbon monoxide laws,” he said.