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.

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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.