Dallas, TX -A woman hurt in a North Texas house explosion that killed her mother and injured other family members has died.

Hazel Sanderson, 44, died Sunday from complications caused by thermal burns, the Dallas County medical examiner’s office said.

Sanderson and four other family members were injured in the May blast in Cleburne, about 30 miles south of Fort Worth.

Her mother, Hazel Pawlick, 64, died days later from her injuries.

Although the home did not use natural gas, fire investigators discovered natural gas had seeped in but gone undetected.

A report by the fire inspector said David Pawlick reported a blue flame sparking when his wife tried to light a cigarette. Fire inspector Scott Oesch said he would check the problem and told David Pawlick not to light any more matches, according to a memo.

Fire Marshal Bill Wright said that before the inspector arrived, David Pawlick lit a match for his wife’s cigarette, sparking an explosion of blue flames in the house.

Sanderson’s father, David Pawlick, is suing Atmos Energy and seeking unspecified damages