Midland, TX – One woman is dead and six other individuals have been released from the hospital after officials say they believe the group was exposed to carbon monoxide early this morning.

Midland fire and EMS officials were called to the 4300 block of Trevino Street on a sick call at 12:17 a.m. today, MFD Assistant Fire Marshal David Hickman said.

When crews arrived a woman was complaining of nausea, vomiting and a headache so they took her into an ambulance to be evaluated and ensure she hadn’t suffered a stroke.

As they were treating her, an individual knocked on the door and alerted them another woman had become ill and was found not breathing inside the home, Hickman said.

When officials went inside the home they found the woman, whose name and age have not yet been released, was already dead, Hickman said.

In total, there were seven people inside the home, which is an assisted living facility for mentally handicapped adults run by Rockhouse.

The caretaker, who had just taken over from another employee at midnight, was the one who called 9-1-1, Hickman said.

The six survivors were transported to Midland Memorial Hospital. The deceased was transported to Tarrant County for an autopsy, Hickman said.

The woman was pronounced dead by Justice of the Peace Joe Matlock.

Hickman said they will need to wait for autopsy results to confirm the incident was the result of CO poisoning, but said all symptoms point toward that as the cause.

The assisted living homes are required by law to be equipped with sprinkler and alarm systems, Hickman said. He said they didn’t see a CO detector in the home during their preliminary investigation.

Following the hail storm and roof replacements throughout town, Hickman said they had warned locals to be sure their vents were still intact, as those can be knocked off when roofs are replaced and lead to CO contamination. However, he said, their investigation thus far shows all the vents were intact inside the Rockhouse home early Wednesday.

The investigation is continuing today and Hickman said they expect autopsy results back within the next few days.