WILMINGTON, D.E., (CBS) — Officials tell Eyewitness News that four individuals have died as a result of an apparent carbon monoxide poisoning at a Wilmington apartment complex.

According to officials, at 5:oo p.m. on Friday, New Castle County Police responded to a welfare complaint at the Evergreen Apartments complex at 500 Homestead Road in Wilmington, New Castle County.

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Upon entry, officers discovered three deceased adults and a deceased dog. Officer say no signs of foul play were apparent.

When it became apparent that an environmental issue could be the cause, officers evacuated the building and found another deceased person in a different apartment.

Officials say seven (four adults, three children) other occupants of the apartment complex are being treated at local hospitals. All are listed in stable condition.

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Officials have not yet said what the caused the levels of carbon monoxide in the apartment building.