ABC spokeswoman Amy Astley released a statement confirming that the envelope was delivered to the show's production office on the CBS Studios lot Friday night.
The statement says ABC was later told by Los Angeles fire officials that the substance was talcum powder.
FBI spokeswoman Laura Eimiller says hazardous materials officials with the city of Los Angeles, LAPD and FBI also responded to the scene on a report of a threatening letter containing white powder. She said an initial screening indicated the substance was not hazardous, but the letter will be transported to a regional lab for further testing.
She says the FBI and LAPD are investigating.