Detroit, MI – Authorities continue to investigate what caused a woman and her five grandchildren to become sick, Local 4 reported.

Ebony Martin, the mother of the children, said she believes the problems started with a faulty furnace at their home in the 15000 block of Bentler Street on Detroit’s west side.

The children’s father apparently attempted to repair the furnace, which may have caused it to leak carbon monoxide, the station reported.

Emergency crews were called to the home at about 4:45 a.m. after Martin’s children and her mother, Emma, were transported to Sinai-Grace Hospital where they were listed in temporary serious condition.

“I’m so upsetI worry about my family and my kids right now,” said Ebony Martin.

Emma Martin was later released from the hospital.

She said she “was mostly dizzy,” but her grandchildren were vomiting. The children remained at the hospital for further treatment.

DTE Energy crews are reportedly having difficulty pinpointing the source of the possible carbon monoxide leak because the house had been aired out by the time they arrived at the scene, the station reported.