Tulsa, OK- TULSA – A family of four is recovering from carbon monoxide poisoning in Tulsa, EMSA officials confirmed Thursday evening.

Tulsa firefighters were called to a north Tulsa home just south of East Pine Street near North Irvington Avenue around 6 p.m. over the possibility of carbon monoxide overexposure.

When crews arrived, the homeowner said he woke up Thursday morning with a migraine — a symptom of CO poisoning — and couldn’t open his eyes.

His daughter, Marilyn Perez, was also ill.

“It’s kind of like a migraine,” she said, describing the effects of CO on her body. “My neck was hurting and stuff.It’s not a normal headache, it’s like a lot of pressure on your head.”

Tulsa Fire Department crews measured a 14 ppm reading, ultimately a low level, but one that can still cause chronic problems if exposed for more than an hour.

Investigators blame the home’s ventless fireplace for the excess carbon monoxide. The gas fireplace was reportedly turned on around 8 p.m. Wednesday and left on until 7 a.m.

TFD spokesman Stan May said Thursday night that the levels may have been even higher before firefighters arrived.

Carbon monoxide is an odorless, colorless, toxic and lethal gas. At 35 ppm, firefighters aren’t allowed to enter a residence.

Neither Marilyn nor her family members were taken to the hospital, with her father choosing to walk outside to clear his system.