A white powder in an envelope with a threatening letter delivered to the "Dancing With the Stars" production office at CBS Studios in Los Angeles was determined to be talcum powder.
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 said 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.
She said an initial screening indicated the substance was not hazardous, but the letter will be transported to a regional lab for further testing, KNBC reported.
She said the FBI and LAPD are investigating.
Los Angeles Fire Department spokesman Brian Humphrey said firefighters also responded to the scene, but no one was treated for injuries.
KCAL-TV reports the powder was found in the mailroom for the ABC show "Dancing With the Stars,'' which is staged on the lot at CBS.
Details of the letter were not revealed.
The FBI would not confirm if any show controversy was behind the unspecified threat, said CBS 2/KCAL 9.
TMZ.com said sources said the powder was in fan mail addressed to teen activist Bristol Palin.
Palin, daughter of former Alaska governor and vice presidential hopeful Sarah Palin, has won viewer votes keeping her on the show despite getting the lowest performance scores from "Dancing With the Stars'' judges, who have praised her improvement over the season.
Singer-actress Brandy was booted off the show last week while the younger Palin was sent on to the finals, which begin Monday night.