FALL RIVER, Mass. (AP) — A Fall River apartment building has been deemed uninhabitable after the release of mercury.

Fire officials say the poisonous material was released into the Hamlet St. building by a man trying to melt down old dental fillings, believing they were silver.

Fall River District Fire Chief Michael Clark said the resident melted the fillings Jan. 25 and went to the hospital three days later. Initially doctors couldn't understand what made him ill.

Toxic levels of mercury were discovered when emergency officials responded to the building Saturday after a 17-year-old girl who lives there became ill. She tested positive for mercury and was transported to a Rhode Island hospital. During the past few weeks three pets in the building died.

Officials said every resident of the building was tested for mercury.