AURORA, Colo. -- An Aurora family sickened by carbon monoxide poisoning early Monday returned home and credits a monoxide detector with saving five lives.

Lisa Barkley and her daughters Daphne, Danielle and Aliya and grandson Isaiah were awakened by the chirping of the alarm at 7 a.m.

"The kids had headaches and nausea," Barkley said. "So we called 911."

"Our equipment did indicate some elevated levels of carbon monoxide in that house," said Deputy Chief Bob Leigh, of the Aurora Fire Department.

The family members were taken to a nearby hospital and were treated with oxygen.

Barkley's husband, Benard Jones, had already left for work when the alarm sounded. He told 7NEWS that he, too, felt lightheaded and nauseous but didn't think anything of it.

After meeting his family at the hospital, he was also treated with oxygen.

Repair crews said that a flue in the attic was apparently damaged by roofers who re-shingled the house over the weekend.

"The elbow, which is the part in the attic, was broken," said Evan Dunn, of Christopher Mechanical. "It caused the flue to vent into the house instead of outside like it's supposed to."

Maintenance manager Ron Jacobs, of Metro properties, told 7NEWS that the alarm was a life saver.

"That thing worked the way it was supposed to," Jacobs said. "Yep, 30 bucks. Perfect Christmas gift right there."

"I'm very thankful everybody’s OK," Jones said. "Especially since we had a 15-month- old baby in the house."

The baby’s mom, Daphne Smith, said she didn't know what to think during the chaos Monday morning.

"He was crying and I was concerned that something bad was going to happen," Smith said. "It scared me when I found out what it was. I was like, 'Oh, let my son be OK."

This isn't the first time that a broken flue has caused problems.

"It's happened a lot," Dunn said. "There was a lot of hail damage last summer, so a lot of roofs are being repaired."

State law mandates that all new homes and all rental homes with new tenants as of July 1, 2009, be fitted with carbon monoxide alarms, if those homes have a fuel burning heater or appliance, a fireplace or an attached garage.

That law was written following the fatal carbon monoxide poisoning of a local family that was spending the Thanksgiving holiday at a home in Aspen.

The bodies of Parker Lofgren, his wife, Caroline, and their son, Owen, and daughter, Sophie, were found by friends who had gone up to Aspen to spend the holiday with them.

The Lofgrens had won the use of the house for a weekend via an auction.