"(CBS/AP) Rat poison has been found in pet food blamed for the deaths of at least 16 cats and dogs, a spokeswoman for the New York State Department of Agriculture and Markets said Friday.

The toxin was identified as aminopterin, state Agriculture Commissioner Patrick Hooker said in a statement. Aminopterin is used to kill rats in some countries, but it's not registered for that use in the United States, according to the Environmental Protection Agency. "

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